KR102533970B1 - Radiation inspection equipment of neutron shield by using neutron source - Google Patents

Abstract

The present invention relates to a radiation inspection device of a neutron shield using a neutron source to inspect the shielding performance of a shield (1) of various neutron generation devices and use facilities discharging neutrons. The radiation inspection device of a neutron shield using a neutron source comprises: a neutron source container (100) installed in a neutron shield (1) of a neutron generation device room, allowing a neutron source (101) used in inspection to be installed therein, and moving up/down, forward/backward, or left/right; a neutron detector (200) installed outside the shield (1) at the same position while the neutron shield (1) is arranged between the shield (1) and the same to detect neutrons passing through the shield (1), and moving up/down, forward/backward, or left/right; and a signal processing module (300) signal-processing the counting rate of neutrons detected by the neutron detector (200) to transmit counting rate data.

Description

Radiation inspection equipment of neutron shield by using neutron source}

The present invention relates to various neutron generators that emit neutrons and a radiation inspection device for neutron shields for inspecting the performance of shields in use facilities, and more particularly, a source container in which a neutron source is loaded is placed inside a neutron shield, It relates to a radiation inspection device for a neutron shield using a neutron source that precisely inspects the shielding performance of the shield by position by disposing a neutron detector outside the shield and then moving them remotely back and forth, left and right.

Radiation inspection of neutron shielding is performed at facilities using nuclear power, radiation, and accelerators that generate large amounts of neutrons, such as spent nuclear fuel handling and processing facilities, isotope production facilities using cyclotrons, and facilities using neutron isotopes. , Medical generator using high-speed energy protons, high-speed energy electron accelerator equipment room for cancer treatment, heavy ion accelerator and proton accelerator facilities, etc. It's about the device.

The neutron source uses the Cf-252 isotope that generates spontaneous fission neutrons, and the Cf-252 isotope is mainly used in the fields of detector and instrument calibration, neutron irradiation of special materials, and performance testing for the development of neutron shields. has been utilized

Since there are some devices and facilities that simultaneously generate gamma rays or neutrons in some nuclear power-related facilities, neutron generators, isotope use facilities, and particle accelerator use facilities, neutrons and gamma rays are reduced and There are times when you need to cover up. Depending on the energy, the way neutrons interact is very different from gamma rays or X-rays. In order to shield fast neutrons, fast neutrons must first be reduced to low-energy thermal neutrons. Paraffin and polyethylene, which contain a lot of hydrogen, are used as shielding materials. There are some problems in terms of structural strength and economy. In addition, some shielding materials absorb neutrons and secondarily re-emit gamma rays due to radiation. Therefore, materials capable of simultaneously shielding neutrons and gamma rays must be used in facilities where fast neutrons are generated. In general, as a material for simultaneously shielding neutrons and gamma rays, concrete or the like is commonly used, but there is a problem in that the thickness of the shielding wall becomes very thick.

In particular, since neutrons can be scattered through gaps and exposed areas of shield walls or devices than gamma rays, dozens of times more radiation may leak. Neutron scattering occurs frequently in the main shielding of facilities generating neutrons, as well as the upper ceilings of some shielding facilities, shielding doors, passages and infiltration pipes, etc., resulting in leakage of radiation much higher than the allowable value.

In neutron generator rooms, such as cyclotrons, proton accelerators, high-energy X-ray generators, and neutron isotopes that generate large amounts of neutrons, shields are installed in structures that form and protect the enclosure, and the neutron shielding performance of these shields is improved. Radiation shield inspection devices for inspection have rarely been developed so far. Therefore, in order to precisely and accurately inspect the shielding performance of the neutron source and the neutron generator user facility, the neutron source is located inside the shield and the neutron detector is placed outside the shield to clearly measure and analyze the measured neutron count rate radiation signal. do. In order to test the performance of these new neutron shields, radiation safety for neutron generators must be further strengthened, and the problem of reducing the thickness of the installed shields and neutron leakage through shield doors and penetration tubes must be solved in advance to ensure safe and effective neutron tests. device is needed

Spent nuclear fuel storage and processing facilities generated from nuclear power plants, isotope production facilities using cyclotrons, neutron isotope use facilities, medical isotope hospital shielding facilities, high-speed energy accelerator equipment rooms for cancer treatment, and heavy ion accelerators and A neutron shield is essential for radiation safety and protection of the human body, such as a proton accelerator use facility. In particular, when producing medical isotopes used in hospitals, a large amount of neutrons are generated when protons emitted from the cyclotron collide particles with the target material of the isotope. Accelerator facilities that use high-speed electron beams (over 40 MeV) to study terahertz (THz) photons also generate large amounts of neutrons. Research on neutron shielding materials and neutron shielding materials that can effectively shield a large amount of fast neutrons generated from high-energy (more than 9MeV) X-ray generators and high-speed energy proton accelerator facilities used in container inspection machines is being actively conducted.

On the other hand, there is a plan to build a heavy ion particle accelerator in the southeast region of Korea, and even when the heavy ion particles collide with a target material, a large amount of neutrons are generated, so a neutron shield must be installed. As the Pohang Accelerator Center also uses high-energy proton beams, a large amount of neutrons are also generated when these high-energy proton beams are irradiated to target materials or specimens. It is likely to be used for Recently, proton beams have been developed and used as medical radiation devices for cancer treatment in Korea, and there are plans to install them in large hospitals in the future. device is needed

In addition, when some hospitals introduce medical cyclotrons, they are designed and installed in a way to shield general X-rays or gamma rays. During radiation safety inspections, a large amount of neutrons leak from shielding walls and points in unexpected locations, resulting in radiation safety. There have been times where problems have occurred. In addition, even in proton accelerator facilities, as a result of measuring the neutron dose rate with a neutron meter in some shielded walls and shielded doors, the neutron dose rate far exceeded the standard value was measured, and there were often cases of refurbishment of the above facilities to reduce it below the standard value. .

As a result of preliminary investigation of neutron-related inspections in existing patent documents, neutrons generated from high-energy X-ray generators used as container detectors, neutrons generated from particle accelerators, and inspection methods using neutron sources are found in Patent Document 1 as follows. to Patent Literature 5.

Looking at the technical content, the security search device using neutron rays and X-rays in Patent Document 1 is a security search device using X-rays and neutrons generated from a high-speed energy (9 MeV or more) X-ray generator. A radiation detection unit located on the opposite side of the radiation generating unit with the test object interposed therebetween, and configured to detect X-rays and neutron rays traveling after passing through the test object, respectively, and may selectively transmit X-rays and neutron rays. It's about a security screening device that's there.

The non-destructive inspection system using neutron rays and X-rays of Patent Document 2 generates X-rays and neutrons in a high-speed energy X-ray generator such as Patent Document 1, and then a radiation generator that irradiates toward an object to be inspected, and the position of the object to be tested is variable. image information of the test object by using a test object moving unit, a radiation detector configured to detect X-rays and neutron rays transmitted through the test object, and radiation information detected from the X-rays and neutron rays transmitted through the test object It relates to a non-destructive inspection system comprising an imaging system for acquiring.

The neutron transmission test apparatus equipped with a particle accelerator of Patent Document 3 uses a neutron generator equipped with a particle accelerator to detect a magnetic field generated from a scintillator of a neutron non-destructive test, and transmits this signal to an analog-to-digital converter to obtain a digital signal. It relates to an apparatus and method for detecting and obtaining an imaging signal for converting to and transmitting to a terminal for visual display.

The mobile neutron transmission test equipment using a small particle accelerator of Patent Document 4 relates to a device for performing a neutron transmission test through a particle accelerator, and more specifically, uses a small cyclotron as a particle accelerator and mounts it on a movable vehicle. It is a device for inspecting a test object in the field by moving directly to a place where non-destructive testing is required. It is a test device characterized by being photographed by a CCD camera installed in the camera, digitally converted, and displayed on the screen of an examiner's terminal.

The land mine detection device by a neutron source of Patent Document 5 and the land mine detection method by a neutron source using the same emit neutrons in which land mines are buried and detect gamma rays generated by the neutrons, but react with nitrogen, the main component of land mines. Detects the gamma-ray intensity of the energy region that shows the largest difference between the spectrum generated by the soil and the spectrum generated by reacting with the soil, classifies the area into a plurality of pixels, and compares the gamma-ray intensity for each pixel. It relates to a device and method for easily checking the embedding position and depth of

The neutron inspection and device method including Patent Documents 1 to 5 as described above uses X-rays or neutrons generated from a high-speed energy X-ray generator to transmit X-rays or neutrons into a container with a security inspection device such as a large container. It is a search device for obtaining images of loaded materials, a device for displaying an image of an object using neutrons emitted from a particle accelerator cyclotron, or a prior art related to a landmine detection device and method using a neutron source.

Patent No. 1 No. 10-2284602 (2021. 07. 27) Patent 2 No. 10-2020-0021495 (2020.02.28.) Patent 3 No. 10-2308130 (2021.09.27.) Patent 4 No. 10-2294946 (2021.08.23.) Patent 5 No. 10-2203984 (2021.01.12.)

The present invention relates to a radiation inspection apparatus for a neutron shield using the neutron source as described above, and the shielding performance of the shield is improved by remotely moving the positions of the collimator and the neutron detector located inside and outside the neutron shield so as to face each other. The purpose is to solve the radiation safety of neutron generators and facilities using them and the resulting problems by providing a shielding performance test device for neutron shields using neutron sources that enable precise inspection by location.

For the purpose as described above, the neutron source container 100 installed inside the neutron shield 1 of the neutron generator room and equipped with the neutron source 101 used for inspection and moving in any one of up and down, front and back, and left and right ; A neutron detector (200) installed outside the shield (1) at the same position with the neutron shield (1) in between to detect neutrons passing through the shield (1) and to move in any one of up and down, forward and backward, and left and right. ); And a signal processing module 300 for signal processing the neutron count rate detected by the neutron detector 200 and transmitting count rate data. It is achieved by a radiation inspection device for a neutron shield using a neutron source.

According to one aspect of the present invention, the neutron source vessel 100, the upper portion is opened by the source vessel lid 105, and one side of the central portion is the source vessel collimator 102, the neutron source 101, and the collimator plug It is characterized in that it consists of a giant (103).

According to another aspect of the present invention, the neutron source is characterized by emitting Cf-252 spontaneous fission fast neutrons.

According to another aspect of the present invention, the neutron source vessel 100 has a guide groove on each side of the square for supporting and moving the source vessel 100, and is vertically fixed at regular intervals. Container moving angle tube 114; Crew vessel vertical movement sub-motor 111 having one end fixed to the movable square tube 114 of the crew vessel 100, installing a support at the upper end, and connected with a cable 113 to the eye bolt 106 at the top of the crew vessel: The lower end of the cable 113 is fixed to the rotating shaft and is pulled while being wound, so that the vertical movement submotor 111 of the crew vessel moves up and down.

According to another aspect of the present invention, the crew vessel 100 includes a plurality of moving wheels 116 installed on the lower surface of the moving support 115 of the crew vessel 100; and a horizontal moving submotor 112 for supplying power to at least two moving wheels among the plurality of moving wheels 116 so that they can move forward and backward or left and right.

According to another aspect of the present invention, the neutron detector 200 is characterized in that it is composed of a neutron detection tube 212 and a preamplifier 211 in a detection cylinder 201, one side of which is open and the other side is blocked.

According to another aspect of the present invention, the neutron detection tube 212 is provided with a He-3 gas detection tube, and the preamplifier 211 has a high voltage (1600V) 301, a power supply (5V) 302, It is characterized by installing a coaxial cable plugger in the signal terminal 303 and increasing the measurement efficiency of the neutron count rate of the signal processing module 300.

According to another aspect of the present invention, the neutron detector 200 has guide grooves corresponding to the protrusions 201 on both sides of the detector 200 and is vertically fixed at regular intervals Four L-shaped detectors a moving corner tube 222; The source detector 200 is fixed to the moving angle tube 222, a support is installed at the top, and the detector vertical movement submotor 221 connected to the top of the detector by a cable 113 and the lower end of the cable 224 are fixed to the rotating shaft, A vertical movement sub-motor 221 of the detector that moves up and down because it is pulled while being wound; It is characterized in that it is configured to further include.

According to another aspect of the present invention, a plurality of moving wheels 223 installed on the lower surface of the moving support 224 of the detector 200; And among the plurality of moving wheels 223, the neutron count rate signal processing module 300 characterized in that it is configured to further include a method of manually moving at least two moving wheels to a manually set position so as to be movable back and forth or left and right. It is characterized in that it further comprises a display means (400) for obtaining neutron count rate data based on the count rate data transmitted from and analyzing it to evaluate the shielding performance of the shield (1) for each position.

According to another aspect of the present invention, the neutron detector is characterized in that it is provided with a He-3 gas detector (He-3 gas detector) to increase the neutron count rate measurement efficiency.

According to another aspect of the present invention, the neutron detector is configured to vertically move the detector by a vertical movement submotor installed on the upper support of the detector, and the horizontal movement of the shield is manually possible as a wheel installed on the lower support. characterized by manipulation.

According to another aspect of the present invention, the crew vessel collimator and the neutron detector are moved to a predetermined position by wired or wireless remote control.

According to another aspect of the present invention, based on the count rate data transmitted from the neutron count rate signal processing module, the count rate data measured by the detector is obtained, and the shielding performance of the neutron shield is evaluated for each location by analyzing the data analysis and It is characterized in that it further comprises a display means (eg, a computer and a monitor).

According to the present invention, the shielding performance of the neutron shield is tested by disposing the neutron source inside the neutron shield, disposing the neutron detector outside the shield, and then moving them remotely to any one of up and down, front and back, and left and right. There is an effect of remotely precisely inspecting the neutron leakage measurement of the facility and the user facility by location.

In addition, the present invention will be used in the future, spent nuclear fuel handling and processing facilities, isotope production facilities using cyclotrons, neutron isotope use facilities, medical generator use facilities using high-speed energy protons, high-speed energy electron beam accelerator equipment rooms, It can be widely used in related facilities where neutrons are generated, such as heavy ion particle accelerators and proton particle accelerators.

1 is a block diagram of the entire system of a shielding performance testing device for a neutron shield using a neutron source according to an embodiment of the present invention.
FIG. 2 is a plan view showing the neutron source container 100 and the neutron detector 200 shown in FIG. 1 as a plane, and a plan configuration diagram showing the source source container and the neutron detector adjacent to the shield door 2 not disclosed in FIG. 1
FIG. 3 is a three-dimensional configuration diagram showing in detail the neutron source container 100 disclosed in FIGS. 1 and 2 .
Figure 4 is a configuration diagram showing in detail the neutron detector and the measurement system disclosed in Figures 1 and 2.
5 is a flow chart of a shielding performance test method and process procedure of a neutron shielding body.
6 is a flowchart showing the operation sequence and procedure of remotely controlling and operating the process of mounting the neutron source in the source container 100 in the neutron shielding body, fixing the movable support, and measuring neutrons using the neutron source.
7A is a cross-sectional view of an electronic calculation simulation model of a shielding performance testing device including a source container and a neutron detector installed inside and outside a neutron shielding body.
7B is a plan view of an electronic calculation simulation model in which a shielding performance testing device including a source container and a neutron detector installed inside and outside a neutron shielding body is installed on a shielding door.
8 is a diagram showing the decrease in the count rate according to the increase in the thickness of the shield as a result of calculating the neutron count rate by estimating that the shielding performance improves as the thickness of the neutron shield (wall) increases.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of the entire system of a shielding performance testing device for a neutron shield (wall) using a neutron source (Cf-252) according to an embodiment of the present invention;

2 is a plan view showing in detail a neutron source container and a neutron detector in which a shielding door is added to the neutron shielding body (wall) disclosed in FIG. 1;

1 and 2, in the radiation inspection apparatus for shielding performance of a neutron shield 1 using a neutron source according to an embodiment of the present invention, the neutron source container 100 is located at the same position with the shield wall 1 interposed therebetween. A detector 200 that is installed outside the shield and detects neutrons passing through the shield and moves in any one of up and down, forward and backward, and left and right, and a count rate signal that processes the neutron count rate measured by the detector 200 and transmits data. Data analysis and display means 400 for obtaining neutron count rate data based on the data transmitted from the processing module 300 and the count rate signal processing module 300, and analyzing it to evaluate the shielding performance of the shielding body for each location. For example, It consists of a computer, a monitor, and a source container 100 generating neutrons emitted from a neutron source of the neutron source container 100.

Here, the neutron source container 100 and the neutron detector 200 are remotely controlled by vertical and horizontal movement sub-motor controllers 213 and 214. In addition, the neutron source vessel 100 and the neutron detector 200 may be mounted on separate supports 115 and 224, respectively.

The neutron source container 100 disclosed in FIG. 3 above is composed of a source container shield 104 as a whole, the upper part is opened with the source container lid 105, and one side of the central part is the source container collimator 102 and the neutron source. (101) and a neutron source vessel (100) with a collimator plugger (103).

The crew vessel 100 includes four moving corner tubes 114 having a guide groove and vertically fixed at regular intervals, a vertical moving submotor 111 on a support at the top of the moving angle tube 114, a rotating shaft and a crew handling container It is composed of a cable 113 connected to four eyebolts 106 on the top, a crew vessel, and a vertical moving submotor 111, so that it can move up and down. In addition, the neutron source vessel 100 applies power to at least two moving wheels among a plurality of moving wheels 116 fixed to the moving support 115 installed on the bottom of the source vessel 100 so as to be able to move forward and backward and left and right. It is configured to further include a horizontal movement sub-motor 112 to provide forward and backward, left and right, that is, horizontal movement is possible.

In addition, the neutron detector 200 disclosed in FIG. 4 is provided with a gas detection tube 212 (He-3 gas tube) to increase the neutron count rate measurement efficiency, and a detection tube having one side sealed and a through hole formed on the other side ( 201) and a detector tube 212 connected to a detector tube preamplifier 211 with high voltage 301, power supply 302 and signal output 303 ports.

This detector 200 has guide grooves corresponding to the protrusions 201 on both sides of the detector 200, and four L-shaped detector moving angle tubes 222 fixed vertically at regular intervals, one end of the detector 200 ) and includes a vertical movement submotor 221 on the support at the top of the moving angle tube 222, a cable 224 connected to a rotating shaft and an upper part of the detector, and a detector and a vertical movement submotor 221, enabling vertical movement. do. In addition, the neutron detector 200 is configured to be movable back and forth or left and right on at least two moving wheels among a plurality of moving wheels 223 fixed to the moving support 224 installed on the bottom surface of the detector 200, Alternatively, left and right, that is, horizontal movement is possible.

In addition, the neutron detector 200 is movable back and forth or left and right on at least two of the plurality of moving wheels 223 and the plurality of moving wheels 223 installed on the moving support 224 of the detector 200. It is configured so that it can move forward and backward or left and right, that is, horizontal movement.

The neutron source container 100 and the detector 200 as described above, that is, the plurality of sub-motors 111, 112, and 221, are located at predetermined positions by wired/wireless remote control using vertical and horizontal movement sub-motor controllers 213 and 214. , and such location control is also possible in real time.

5 is a flow chart of a method of inspecting radiation for shielding performance of a neutron shield (wall) and a process procedure.

According to FIG. 5, before inspecting the shielding performance of the neutron shield, the manager mounts the Cf-252 neutron source 101 in the source container 100 (S1). Subsequently, the manager manipulates the vertical and horizontal movement sub-motor controllers 111 and 112 to drive the plurality of sub-motors 111, 112 and 221 to move the source vessel 100 and the neutron detector 200 up and down, forward and backward, and forward and backward. It is moved to one of the left and right sides to move to a position for inspecting the shielding performance of the neutron shield (S2, S3).

After the neutron source vessel 100 and the neutron detector 200 are moved to the position to be measured, radiation emitted from the neutron source 101 passes through the shield and is detected by the neutron detector tube 212 is measured. (S4).

As described above, the neutron measurement signal detected by the neutron detection tube 212 is transmitted to the neutron count rate signal processing module 300, and the neutron count rate is obtained by the neutron count rate signal processing module 300 and displayed (S5).

Subsequently, the data analysis and display means 400 receiving the information on the neutron count rate, for example, a computer and a monitor, analyzes the measured count rate level (S6), detects a high level of the neutron count rate at the set position, After checking the shielding performance, it is displayed on the screen (S7).

Then, in order to test the shielding performance of the neutron shielding body at the next position, the plurality of sub-motors 111, 112, and 221 are driven to move the source vessel 100 and the detector 200 to the next position (S8). . Then, the count rate measured at all measurement positions of the shield is analyzed and evaluated (S9).

6 is a flow chart of a working procedure and inspection process for the shielding performance test of the neutron shielding body.

According to FIG. 6, an important task to be prepared in advance before testing the shielding performance with a neutron source is to attach the externally purchased Cf-252 neutron source 101 to the source container 100 and cover the source handling container. It is opened and a source is installed in the source capsule stored therein (S10). After the source is safely mounted, a manager performs a dose test on the surface of the container with a portable neutron detector, and then the manager moves the source container into the shield of the neutron generator room (S11). The neutron source container is placed on the movable support 115 and fixed (S12).

The collimator plugger 103 is taken out from the crew vessel collimator 102 of the crew vessel 100 and temporarily moved to the movable support 115, and the crew vessel support 115 is moved to the shield measurement position (S13) . After the neutron detector 200 is moved to the movable support 224 and fixed, the detection tube 212 is inserted into the detection cylinder 201 and fixed (S14).

Attach the preamplifier 211 to the neutron detection tube 212, and install the coaxial cable plugger on the high voltage (1600V) (301), power supply (5V) (302), and signal terminal (303) on the preamplifier (211) (S15). Connect the high voltage (301), power supply (302), and signal terminal (303) cable plugger to the signal processing module (300) (S16), and the vertical and horizontal movement submotor of the crew vessel collimator (102) and the detector (200) The measurement position is set by the controllers 213 and 214 of (111 and 112).

When the positions of the neutron source vessel collimator 102 and the detector tube 212 are set (S17), the neutron count rate is checked by the count rate number of the LED window 304 attached to the signal processing module 300, and the data is analyzed and displayed. Means 400, for example, transmits the data to a computer and monitor, stores it for each location, inspects and confirms it (S18, S19).

7A and 7B are plan views and cross-sectional views of an electronic calculation simulation model of a shielding performance test device including a neutron source vessel and a detector installed inside and outside a neutron shielding body (wall).

Here, the neutron shielding body 1 is composed of a concrete wall with a thickness of about 70 cm capable of shielding neutrons. As such, the construction of concrete walls is mainly used for narrow work spaces in general hospitals or relatively small accelerator facilities, and for future movable facilities. The distribution of the neutron count rate detected according to the thickness of the shield in the computer model in the vicinity of the neutron detector 200 is shown in FIG. 8. It was found that the neutron count rate increased to about 580 n/s when the thickness of the concrete was about 45 cm.

Since the description of the present invention described above is only an embodiment for structural or functional description, the scope of the present invention should not be construed as being limited by the embodiment described in the text. That is, the present invention is not limited by the foregoing embodiments and the accompanying drawings, but is limited by the claims to be described later, and the configuration of the present invention is variously changed within a range that does not deviate from the technical spirit of the present invention. And since it can be modified, the embodiment of the present invention can be variously changed and can have various forms. Accordingly, it should be understood that the scope of the present invention includes equivalents capable of realizing the technical idea.

1: neutron shielding body (wall) 2: shielding door
100: neutron source vessel 101: neutron source
102: sailor vessel collimator 103: collimator plugger
104: Crew vessel shield 105: Crew vessel lid
106: eye bolt 111: neutron source container vertical movement submotor
112: crew vessel horizontal movement motor 113: cable
114: Crew vessel movable angle tube 115: movable support
116: moving wheel 200: neutron detector
201: detection tube 211: detection tube preamplifier
212: detection tube (He-3 tube) 213: horizontal movement servomotor controller
214: vertical movement sub-motor controller 221: detector vertical movement sub-motor
222: detector moving angle tube 223: moving wheel
224: moving support 300: count rate signal processing module
301: high voltage 302: power supply
303: signal output 304: LED display
400: computer

Claims (10)

It is installed inside the neutron shield (1) of the neutron generator room and used for inspection,
A neutron source 101 that emits Cf-252 spontaneous fission fast neutrons is mounted, and moves in any one of up and down, front and rear, and left and right, the upper part is opened with the source container lid 105, and one side of the central part is the source container collimator. 102, a neutron source 101, and a collimator plugger 103,
Four L-shaped moving angle tubes 114 for a crew member container 114 having guide grooves on four sides for supporting and moving the crew member container 100 and fixed vertically at regular intervals; A crew vessel vertical movement sub-motor 111 having one end fixed to the movable corner tube 114 of the crew vessel 100, a supporter installed at the upper end, and connected to the eye bolt 106 at the top of the crew vessel by a cable 113; It consists of a vertical movement submotor 111 of a crew vessel that moves up and down as the lower end of the cable 113 is fixed to the rotating shaft and pulled while being wound.
a plurality of movable wheels 116 installed on the lower surface of the movable support 115 of the crew vessel 100; and a neutron source vessel 100 comprising a horizontally moving sub-motor 112 for providing power to at least two of the plurality of moving wheels 116 so as to be able to move back and forth or left and right;
It is installed outside the shield 1 at the same location with the neutron shield 1 in between to detect neutrons passing through the shield 1 and move in any one of up and down, front and back, and left and right, one side being open It is composed of a neutron detection tube 212 and a preamplifier 211 in the detection cylinder 201 blocked on the other side, and has guide grooves corresponding to the projections 201 on both sides of the neutron detector 200 and is spaced at a certain interval. Four L-shaped detector moving angle tubes 222 fixed vertically; The neutron detector 200 is fixed to the moving angle tube 222, a support is installed at the top, and the detector vertical movement submotor 221 connected to the top of the detector by a cable 224 and the lower end of the cable 224 are fixed to the rotating shaft The vertical movement sub-motor 221 of the detector moves up and down because it is pulled while being wound; A plurality of moving wheels 223 installed on the lower surface of the moving support 224 of the neutron detector 200 consisting of; And among the plurality of moving wheels 223, the neutron detector 200 configured to include a method of manually moving at least two moving wheels to a manually set position so as to be movable back and forth or left and right;
The neutron detection tube 212 is provided with a He-3 gas detection tube, a high voltage (1600V) 301 to the preamplifier 211, a power supply (5V) 302, and a coaxial cable plug to the signal terminal 303 It is composed of a signal processing module 300 that installs a filter, increases the measurement efficiency of the neutron count rate of the signal processing module 300, processes the neutron count rate detected by the neutron detector 200, and transmits count rate data,
Characterized in that it comprises a display means 400 for obtaining neutron count rate data based on the count rate data transmitted from the neutron count rate signal processing module 300 and evaluating the shielding performance of the shield 1 for each position by analyzing it A radiation inspection device for a neutron shield using a neutron source.
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