[en] We has been developed two remotely controlled robotic systems. One is a underwater vehicle for inspection of the internal structures of PWRs and retrieving foreign stubs in the reactor pressure vessels and reactor coolant pipes. The other robotic system consists of a articulated-type mobile robot capable of recovering the failure of the fuel exchange machine and a mini modular mobile robot for inspection of feeder pipes with ultrasonic array sensors in PHWRs. The underwater robot has been designed by considering radiation effect, underwater condition, and accessibility to the working area. The size of underwater robot is designed to enter the cold legs. A extendable manipulator is mounted on the mobile robot, which can restore nuclear fuel exchange machine. The mini modular mobile robot is composed of dual inch worm mechanisms, which are constructed by two gripper bodies that can fix the robot body on to the pipe and move along the longitudinal and to rotate in a circumferential direction to access all of the outer surfaces of the pipe

[en] We developed the tele-robotic systems for inspection/maintenance of steam generator tubes. For easy handling and installation, it consists of three separable parts: the entering/leaving device, the base posture adjusting device, the manipulator. The inspection and repair tools, such as brushing, plugging, and sleeving tools, were developed. We also developed software programs for the eddy current test signal acquisition and evaluation. The semiconductor type dosimeter and the directional radiation mapping module were developed for measuring the accumulated radioactivity and for finding the radioactivity source location. The research for radiation shield and decontamination were carried out. The developed robotic system has been tested in the Ulchin NPP type steam generator mockup in our laboratory, and after evaluation and some modification the final functional test was carried out at the Kori NPP type steam generator mockup in the Kori training center

[en] This report has described the software safety analysis techniques and the engineering guidelines for developing safety critical software to identify the state of the art in this field and to give the software safety engineer a trail map between the code and standards layer and the design methodology and documents layer. We have surveyed the management aspects of software safety activities during the software lifecycle in order to improve the safety. After identifying the conventional safety analysis techniques for systems, we have surveyed in details the software safety analysis techniques, software FMEA(Failure Mode and Effects Analysis), software HAZOP(Hazard and Operability Analysis), and software FTA(Fault Tree Analysis). We have also surveyed the state of the art in the software reliability assessment techniques. The most important results from the reliability techniques are not the specific probability numbers generated, but the insights into the risk importance of software features. To defend against potential common-mode failures, high quality, defense-in-depth, and diversity are considered to be key elements in digital I and C system design. To minimize the possibility of CMFs and thus increase the plant reliability, we have provided D-in-D and D analysis guidelines

[en] Two diverse control platforms have been developed for application to safety I and C systems which have capability to mitigate CCFs under the project funded by the Korean Ministry of Trade, Industry and Energy. In this project Susan E and S develops the microprocessor based control platform named SPLC and Doosan Heavy Industry is in charge of developing the FPGA based control platform named DFLC-N. This paper describes the typical diversity strategies which can be implemented in safety I and C systems and introduces two safety grade control platforms being developed to improve the diversity of safety I and C systems. Two control platforms have been developed for application to safety I and C systems under the project funded by the Korean Ministry of Trade, Industry and Energy. In this project Susan E and S develops the microprocessor based control platform and Doosan Heavy Industry is in charge of developing the FPGA based control platform In this paper the typical diversity strategies implemented in safety I and C systems were described and the design concept of two safety grade platforms was introduced for mitigating the CCF vulnerabilities

[en] In general, the software development life cycle consists of the requirement phase, design phase, implementation phase, testing phase, integration phase (software-software integration, software-hardware integration), installation phase, and operation and maintenance phase. The fundamental parts to the testing phase are component test, software integration test, software hardware integration test, and system test. Among these tests, we focused in particular on system test using I/O stimulator. The system test operates the functionality, performance, and interface because system testing falls within the scope of black box testing, which should not require knowledge of the inner design of the code or logic. The purpose of developing a system test using a I/O stimulator is to save time and effort from the functionality and performance tests. We developed an I/O stimulator for the burning system test based on the operational scenario. The hardware, software, and manmachine- interface (MMI) are fundamental parts to the I/O stimulator. Signal sources from the I/O stimulator contain analog input, analog output, digital input, digital output, a Programmable Power Supply, an RS232C Serial interface and a dual port Ethernet interface. While automation cannot reproduce everything that a software engineer can do, it can be extremely useful for the system test. However, it does require the test criteria and a well-developed test suite of the testing scripts in order to be useful. In this study, we developed a multipurpose and cost-efficient I/O stimulator using LabVIEW program instead of the testing scripts

[en] When a big disaster occurs in the nuclear facilities as like the JCO criticality accident, the sensing head module, which gathers a critical information such as radioactivity leakage, whole damage image and the outline of a stricken facility, is required. The sensing head module is mounted on the lightweight, compact, and mobile robot for nuclear facility emergency preparedness and response. And the sensing head module must be equipped with the stereo camera system and the thermal infrared camera system as the image acquisition unit. The thermal infrared camera have the superior observation characteristics compared to the color ccd camera in disastrous facilities covered with dust and steam vapours. Through the development of the technique of superimposing thermal infrared image into color CCD image, the more accurate and clear observation performance for unstructured area such as disastrous nuclear facilities, covered with dust and steam vapours, can be obtained. The enhanced inspection performance will do much for planning the preparedness and emergency for accidents in nuclear power plant

[en] Working in radiation environment such as nuclear power plant, RI facility, nuclear fuel fabrication facility, medical center has to be considered radiation exposure, and we can implement these job by remote observation and operation. However the camera used for general industry is weakened at radiation, so radiation-tolerant camera is needed for radiation environment. The application of radiation-tolerant camera system is nuclear industry, radio-active medical, aerospace, and so on. Specially nuclear industry, the demand is continuous in the inspection of nuclear boiler, exchange of pellet, inspection of nuclear waste. In the nuclear developed countries have been an effort to develop radiation-tolerant cameras. Now they have many kinds of radiation-tolerant cameras which can tolerate to 10⁶-10⁸ rad total dose. In this report, we examine into the state-of-art about radiation-tolerant cameras, and analyze these technology. We want to grow up the concern of developing radiation-tolerant camera by this paper, and upgrade the level of domestic technology

[en] Highlights: • A methodology to evaluate actuators of a dismantling manipulator. • Evaluation criteria for choosing the most suitable actuator type. • A mathematical evaluation model for evaluation. • The evaluation method is expected to be used for determining other manipulators. - Abstract: This paper presents a methodology to evaluate actuators of a manipulator for dismantling nuclear power plants. Actuators are the most dominant components because a dismantling manipulator relies heavily on the actuator type used. To select the most suitable actuator, evaluation criteria are presented in four categories based on the nuclear dismantling environment. A mathematical model is presented and evaluation results are calculated with weights and scores for each criterion. The proposed evaluation method is expected to be used for determining other aspects of the design of dismantling manipulators.

[en] Today’s tele-operated robots are mainly mobile robots, and are still at a low level of technology. They don’t work well remotely in a complex unstructured environment without human intervention. Fully autonomous robots are the goal, but tele-operated robots working in the harsh environment such as radiation-contaminated area, deep sees and space are essential for a long time. As human beings expand in the extreme environment of exploration, continuous research and possession of remote control technology is an essential element for future national competitiveness. We developed a core tele-operation technology such as a real time generation of virtual guidances using feature extracting algorithm and trajectory planning using human intuition and computation ability of computer, a shared control technology to remotely control the combined system with high degree of freedom robots and a flexible system. We established a standard system of work process based on unit work to overcome the limitations of human operator’s spatial cognitive and operation ability. And we developed a method to provide operator-oriented egocentric views, a master interface device and method according to viewpoint changes with intuitive and minimal manipulation, and an AR display and a visuo-haptic feedback method to assist/improve operator’s cognitive ability by applying AI technique. We reduced a working time of NPP’s maintenance element task by 50% with the developed core tele-operation technology and demonstrated a control performance to carry out a peg-in-hole task with +/-1mm clearance despite the base disturbance. And we successfully carried out tele-operated pipe cutting/welding tasks.

[en] In this research, a outdoor wheel-type walking-assist device is developed to help an elder having a poor muscular strength at legs for walking, sitting and standing up easily at outdoors, and also for going and downing stairs. In conceptually designing, the environments of an elder's activity, the size of an elder's body and a necessary function of helping an elder are considered. This device has 4 wheels for stability. When an elder walks in incline plane with the proposed device, a rear-wing is rotated to keep the supporting device horizontal, regardless of an angle of inclination. A height-controlling device, which can control the height of the supporting device for adjusting an elder's height, is varied vertically to help an elder to sit and stand-up easily. Moreover, a outdoor wheel-type walking-assist device is conceptually designed and is made. In order to design it, the preview research is investigated firstly. On the basis of the proposed walking-assist device, the outdoor walking-assist device is designed and made. The outdoor wheel-type walking-assist device can go and down stairs automatically. This device go up and down the stair of having maximum 20cm height and an angle of 25 degrees with maximum 4 sec/stairs speed, and move at flatland with 60cm/sec speed