From the viewpoint of disaster prevention, it is expected the unmanned automation of daily inspection/health monitoring and diagnostic work for facilities/structures in places where it is difficult to let the inspectors going such as offshore plant and dangerous places. By adopting remote controlled/autonomous robot, regarding the occurrence of abnormality due to human factors, breakage of facilities due to aging of facilities, malfunction caused by them, accidents by increasing the frequency of periodic inspection, it becomes possible to prevent it in advance. In addition, introduction of the robot makes it possible to conduct inspection work even during operation, so it is expected that the availability factor of facilities in such environment will be improved. This paper described about the plant disaster prevention challenge of the World Robot Summit 2020 disaster robotics category held at the Fukushima Robot Test Field in October 2021. The competition concept and the competition rule were introduced. The analysis of the competition results were shown and considered based on competition results. Finally, the lessons learned was mentioned.