Application of Robotic System for Emergency Response in NPP

Increasing energy demand and concerns over climate change make increasing use of nuclear power plant in worldwide. Even though the probability of accident is greatly reduced, safety is the highest priority issue in the nuclear energy industry. Applying highly reliable and conservative 'defense in depth' concepts with the design and construction of NPP, there are very little possibilities with which accidents are occur and radioactive materials are released to environments in NPP. But NPP have prepared with the emergency response procedures and conduct exercises for post-accident circumstance according to the procedures. The application of robots for emergency response task for post-accident in nuclear facilities is not a new concept. Robots have been sent to recover the damaged reactor at Chernobyl where human workers could receive a lifetime dose of radiation in minutes. Based on NRC's TMI-2 Cleanup Program, several robots were built in the 1980s to help gather information and remove debris from a reactor at the Three Mile Island nuclear power plant that partially melted down in 1979. The first robot was lowered into the basement through a hatch and human operators monitoring in a control room drove it through mud, water and debris, capturing the initial post-accident images of the reactor's basement. It was used for several years equipped with various tools allowing it to scour surfaces, scoop samples and vacuum sludge. A second version carried a core sampler to determine the intensity and depth of the radiation that had permeated into the walls. To perform cleanup tasks, they built Workhorse that featured system redundancy and had a boom extendable to reach high places, but it was never used because it had too many complexities and to clean and fix. While remote robotics technology has proven to remove the human from the radioactive environment, it is also difficult to make it useful because it may requires skill about remote control and obtaining remote situation awareness regardless of the actual task. The efficiency of the human-robot interaction is very important to obtain the overall goal for the emergency response in timely manner. It would be a bottle-neck to apply the robotic technology for carrying the emergency response in NPP. Simple remote operation schemes are not adequate, more intelligent autonomous operation schemes are required to enhance the effectiveness of robots for the emergency response. This paper presents recent trends in development of robotic technologies enhancing their autonomy for the emergency response in other countries. It also provides some basic research activities for the application of robotic system for emergency response in our institute