• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.285-294
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• 2023

Autonomous radiation source detection has long been studied for radiation emergencies. Compared to conventional data-driven or path planning methods, deep reinforcement learning shows a strong capacity in source detection while still lacking the generalized ability to the geometry in unknown environments. In this work, the detection task is decomposed into two subtasks: exploration and localization. A hierarchical control policy (HC) is proposed to perform the subtasks at different stages. The low-level controller learns how to execute the individual subtasks by deep reinforcement learning, and the high-level controller determines which subtasks should be executed at the current stage. In experimental tests under different geometrical conditions, HC achieves the best performance among the autonomous decision policies. The robustness and generalized ability of the hierarchy have been demonstrated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.2001-2006
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• 2016

The stereo radiation detection system detects the gamma source and acquires two dimensional left and right images for gamma source and visible objects using the detection result. And then the system measures the distance to the radiation source from the system in 3D space using stereo vision algorithm. In this paper, we implemented the fast detection algorithm for gamma source from the system in 3D space to reduce the detection time with image processing algorithms. Additionally, the system's performance is verified through experiments on gamma irradiation facilities. As a result, if the fast detection algorithm applied to the system, we can confirm that the detection system represents a 35% better performance than the conventional detection method that is full scanning to acquire the stereo image. We also have visualized a gamma source distribution through a 3D monitor using the stereo vision algorithm in order to provide the information of radiation spatial distribution to the user efficiently.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.612-615
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• 2003

In this paper, a design of radiation detector for gamma column scanner is introduced. Distillation column is important unit in Petro-chemical industries, and its on-line diagnose is very important. To get density profile measured by the radiation transmitted through column is well method for on-line diagnose as gamma scanning. For this purpose radiation detection circuit, radiation source and mechanical system for moving source and detector are required. Conventional radiation detection circuit for this application is sensitive to electric noise because of interface between the radiation circuit and the controller for mechanical system. The radiation detection system introduced here is using loop coil instead of slip ring to remove contact noise. Radiation detection system designed here for gamma scanning consist of BGO detector, high voltage circuit, PHA circuit and FSK modem. The BGO detector is used as radiation sensor, high voltage circuit and peak height analysis circuit is essential to process the signal generated from BGO detector. Micro controller convert measured data into ASCII data. FSK modem transmit ASCII data. Transmitted ASCH data is picked up in antenna coil and processed for combined function with mechanical system. This method gives good result by isolating the controlling circuit of mechanical system from radiation detecting circuit which is sensitive to noise.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.1031-1033
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• 2013

Radiation protection, as well as finding the location of the radiation source, such as the Fukushima radiation leak accident, it is important for the early and safe disposal of nuclear accident. The three-dimensional position of the radiation source detection distance of the radiation source can provide additional information to the existing radiation detectors radiation of a two-dimensional position detection function and then it can play a decisive role in the radiation contaminant removal and decontamination work. In this research, three-dimensional semiconductor sensor based on dual radiation detectors radiation source device visible part of the research and development of efficient radiation sensor unit on the design of the shielding structure.The lightweight, high-efficiency radiation source locator implementation was attempted for the structure and thickness of the shielding and collimator to perform the simulation of the radiation shielding for the various parameters of the shape model through design the optimal structure of the MCNP-based heavy-duty tungsten shielding, lead shielding The results of this study, is a compact, lightweight three-dimensional radiation source detection and future of silicon - based sensors will be used in the study.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1130-1132
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• 2007

In this research, 3D position exploring system was developed to detect direction and position of radiation source by using two general CCD camera. This system consists of a radiation detection device, a controlling device, and a monitoring device. A radiation detection device is composed of a collimator, a scintillator, CCD sensor, and radiation shielding part. Incident radiation is firstly collimated with direction and converted into visual lights in a scintillator. The CCD sensor detect the converted visual light and send a signal as an image. This can explore a radiation source with direction and distance from geometrical structure of two sensors. From these information, the developed 3D position exploring system can provide 3D radiation source information. This research will be useful for managing and processing radioactive materials in remote.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1103-1105
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• 2015

Leaked Radioactive source in nuclear power station, radiation related facilities and the aging nuclear power plant for the dismantling must need to detect and remove early to prevent major accidents. In this paper, we implemented a single sensor-based gamma-ray detectors stereo which can provide the distance to the radiation source, a direction and doserate information for fast and efficient decontamination work the radiation source. And we have carried out an algorithm development for high-speed detection of the detection equipment. Two detectors are required for stereo structure for obtaining the distance information of the radioactive source, but we designed the only sensor-based detection device for the weight reduction. We have extracted the region of interest and obtained the distance calculation result and distribution of radiation source in order to minimize a stereo image acquisition time. Detection time of the algorithm showed a shorter time of about 41%.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2412-2420
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• 2024

The International Atomic Energy Agency (IAEA) mandates safeguards to ensure non-proliferation of nuclear materials. Among inspection techniques used to detect partial defects within spent nuclear fuel (SNF), gamma emission tomography (GET) has been reported to be reliable for detection of partial defects on a pin-by-pin level. Conventional GET, however, is limited by low detection efficiency due to the high density of nuclear fuel rods and self-absorption. This paper proposes a new type of GET named Spent Fuel Internal Tomography (SFIT), which can acquire sinograms at the guide tube. The proposed device consists of the housing, shielding, C-shaped collimator, reflector, and gadolinium aluminum gallium garnet (GAGG) scintillator. For accurate attenuation correction, the source-distinguishable range of the SFIT device was determined using MC simulation to the region away from the proposed device to the second layer. For enhanced inspection accuracy, a proposed specific source-discrimination algorithm was applied. With this, the SFIT device successfully distinguished all source locations. The comparison of images of the existing and proposed inspection methods showed that the proposed method, having successfully distinguished all sources, afforded a 150 % inspection accuracy improvement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1535-1541
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• 2019

To carry out safe and rapid decontamination in radiological accident areas, acquisition of various information on radiation sources is needed. In particular, to figure out the location and distribution of radiation sources is essential for rapid follow-up and removal of contaminants as well as minimizing worker damage. The radiation distribution detection device is used to obtain the position and distribution information of the radiation source. In the case of a radiation distribution detection device, a detection sensor unit is generally composed of a single sensor, and the detection range is limited due to the physical characteristics of the single sensor. We applied a calibration detector for controlling the detection sensitivity of a single sensor for radiation detection and improved the limited detection range of radiation dose rate. Also, gamma irradiation test confirmed the improvement of radiation distribution detection range.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.780-781
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• 2016

The stereo radiation detection system detects gamma ray source and measures the two dimensional distribution image based on the detection result. Then the system is implemented to measure the distance to the radiation source from the system in 3D space using stereo vision algorithm. In this paper, we reduced the time for a gamma-ray scan space detection through image processing algorithms. In addition, it combines radiation and visible light images. Then we conducted a study for improving the distribution of gamma-ray detection efficiency through the stereo calibration using a 3D visualization. As a result, we obtain an improved detection time by more than 30% and have acquired a visible image with a 3D monitor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.707-709
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• 2014

The radiation sources leaked from large-scale radiation leak accident like the Fukushima nuclear power plant accident or nuclear explosions can cause to the very large damage for us. So that the damage can be minimized, we have being developed a detector that can providing information about the location of the source to remove dangerous substances quickly than the conventional single detector. In this paper, we designed and implemented the radiation shield and the collimator for the development of the stereo radiation detector to detect contamination things using MCNP Simulation. And we analysed the test results of the radiation shield and collimator using the radiation source. The results of this paper will be used as the basis for improving the efficiency of the stereo radiation detector being studied currently.