• International Journal of Control, Automation, and Systems
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• 제4권1호
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• pp.87-95
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• 2006

The outlet feeder pipe thinning in a PHWR (Pressurized Heavy Water Reactor) is caused by a high pressure steam flow inside the pipe, which is a well known degradation mechanism called a FAC (Flow Assisted Corrosion). In order to monitor the degradation, the thickness of the outlet bends close to the exit of the pressure tube should be measured and analyzed at every official overhaul. This paper describes a mobile feeder pipe inspection robot that can minimize the irradiation dose to human workers by automating the measurement process. The robot can move by itself on the feeder pipe by using an inch worm mechanism, which is constructed by two gripper bodies that can fix the robot body on to the pipe, one extendable and contractible actuator, and a rotation actuator connected to the two gripper bodies to move forward and backward, and to rotate in a circumferential direction.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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• pp.193-196
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• 2002

In this paper, we presents the remote inspection activity with a mobile robot at the calandria face areas of the PHWR (pressurized heavy water reactor) nuclear power plants during full power plant operation.. The tele-operated mobile robot has been developed for this task. A 4 wheeled mechanism with the dual reconfigurable crawler arm has been adopted for the ease access to the high radiation area of calandria face. A specially designed extendable long reach mast attached on the mobile platform and the thermal image monitoring system enable human eyes to look into the calandria face. Application of robot will keep human workers from high radiation exposure and enhance the reliability of nuclear power plants.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4695-4702
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• 2023

Nuclear power plants play a pivotal role in the global energy infrastructure, fulfilling a substantial share of the world's energy requirements in a sustainable way. The management of these facilities, especially the handling of spent nuclear fuel (SNF), necessitates meticulous inspections to guarantee operational safety and efficiency. However, the prevailing inspection methodologies lean heavily on human operators, which presents challenges due to the potential hazards of the SNF environment. This study introduces the design of a novel Pre-Batched Inspection Strategy (PBIS) that integrates robotic automation and image processing techniques to bolster the inspection process. This methodology deploys robotics to undertake tasks that could be perilous or time-intensive for humans, while image processing techniques are used for precise identification of SNF targets and regulating the robotic system. The implementation of PBIS holds considerable promise in minimizing inspection time and enhancing worker safety. This paper elaborates on the structure, capabilities, and application of PBIS, underlining its potential implications for the future of nuclear energy inspections.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1263-1264
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• 2011

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.1349-1350
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• 2005

• Nuclear Engineering and Technology
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• 제49권7호
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• pp.1414-1422
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• 2017

Remote response technology has advanced to the extent that a robot system, if properly designed and deployed, may greatly help respond to beyond-design-basis accidents at nuclear power plants. Particularly in the aftermath of the Fukushima accident, there is increasing interest in developing disaster robots that can be deployed in lieu of a human operator to the field to perform mitigating actions in the harsh environment caused by extreme natural hazards. The nuclear robotics team of the Korea Atomic Energy Research Institute (KAERI) is also endeavoring to construct disaster robots and, first of all, is interested in finding out to what extent safety benefits can be achieved by such a disaster robotic system. This paper discusses a new approach based on the probabilistic risk assessment (PRA) technique, which can be used to quantify safety benefits associated with disaster robots, along with a case study for seismic-induced station blackout condition. The results indicate that to avoid core damage in this special case a robot system with reliability > 0.65 is needed because otherwise core damage is inevitable. Therefore, considerable efforts are needed to improve the reliability of disaster robots, because without assurance of high reliability, remote response techniques will not be practically used.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1669-1676
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• 2020

The IAEA held the IAEA Robotics Challenge 2017 (IRC2017) to protect workers during inspections of spent nuclear fuel and to improve work efficiency and accuracy rates. To this end, we developed an unmanned surface vehicle (USV) system called the spent fuel check vehicle (SCV). The SCV extracts and tracks the target through image processing, and it is necessary to find suitable parameters for the SNF storage environment in advance. This preliminary work takes time. It is also difficult to prepare the environment in which the work will proceed. In addition, if the preliminary work does not proceed as planned, the system will not move at the proper speed and will become unstable, with yawing and overshoot. To solve this problem, we developed a controller with a camera that can extract the depth at which the target is stored and allow distance-adaptive control. This controller is able to attenuate system instability factors such as yawing and overshoot better than existing controllers by continuously changing system operation parameters according to the depth. In addition, the time required for preliminary work during inspections can be shortened.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.430-432
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• 2004

Tele-operation and remote monitoring techniques are essential and important technologies for the inspection and maintenance of the radioactive waste. A mobile robot has been developed for the application of remote monitoring and inspection of nuclear facilities, where human access is limited because of the high-level radioactive environments, The mobile robot was designed with reconfigurable crawler type of wheels attached on the front and rear side in order to pass through the ditch, The extendable mast, mounted on the mobile robot, car be extended up to 8 m vertically. The robust controller for radiation is designed in focus on electric components to prevent abnormal operation in a highly radioactivated area during reactor operation, This robot system will enhance the reliability of nuclear power facilities, and cope with the unexpected radiation accident.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.415-415
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• 2000

The functions of a mobile robot such as obstacle knowledge and collision avoidance for in-door cleaning are necessary features, as has been much studied in the field of industrial automatic guided vehicle or general mobile robot. A mobile robot, in order to avoid collision with obstacles, has to gather data with environment knowledge sensors and recognize environment and the shape of obstacles from the data. In the study, a wall-following algorithm was suggested as a autonomous moving algorithm in which a mobile robot can recognize obstacles in indoor like environment and do cleaning work in effect. The system suggested in the study is for cleaning of nuclear material dusts generated in the process of nuclear fuel manufacturing and decontamination of devices in disorder which is performed in M6 radioactive ray shield hot-cell in IMEF(Irradiated Material Examination Facility) in the Korea Atomic Energy Research Institute.

• Nuclear Engineering and Technology
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• 제56권7호
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• pp.2718-2731
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• 2024

To ensure the operational safety of nuclear power plants, we present a Quadruped Inspection Robot that can be used for many types of steam generators. Since the Inspection Robot relies on the Holding Modules to grip the tube-sheet, it can be regarded as a hybrid robot with variable configurations, switching between 4-RRR-RR, 3-RRR-RR, and two types of 2-RRR-RR, and the variable configurations bring a great challenge to dimensional synthesis. In this paper, the kinematic model of the Inspection Robot in multiple configurations is established, and the analytical solution is given. The workspace mapping is analyzed by the solution-space, and the workspace of multiple configurations is decomposed into the workspace of 2-RRR to reduce the analysis complexity, and the workspace calculation is simplified by using the envelope rings. The optimization problem of the manipulator is transformed into the calculation of the shortest contraction length of the swing leg. The switching performance of the Inspection Robot is evaluated by stride-length, turning-angle, and workspace overlap-ratio. The performance indexes are classified and transformed based on the proportions and variation trends of dimensional parameters to reduce the number of optimization objective functions, and Pareto optimal solutions are obtained using an intelligent optimization algorithm.