AUTONOMOUS MOVEMENT TECHNOLOGY FOR REDUCING DECOMMISSIONING WORKLOAD IN HIGH-DOSE ENVIRONMENTS

抄録

At Units 1 to 3 of the Fukushima Daiichi Nuclear Power Plant, it is believed that nuclear fuel melts together with the structures inside the reactor and exists as fuel debris in the Primary Containment Vessel (PCV), including the Reactor Pressure Vessel (RPV). Therefore, it is necessary to perform fuel debris retrieval work and environment maintenance work for retrieval under a high-dose environment, and remote technology is essential. Since these operations require an enormous number of repetitive operations, autonomous mobility of remote-controlled robots is considered effective in reducing the burden on workers. Generally, laser rangefinders are used for autonomous movement, but they do not have high radiation resistance. In this paper, we construct a pseudo-stereo camera by combining a radiation-resistant camera and a mirror, and propose an environmental recognition technology using the acquired images and ranging information. In the proposed technology, we developed a camera system that uses SiC semiconductors with high radiation resistance as the control board and installed it on a remote-controlled robot. In addition, we have developed a system that prevents video deterioration and acquires useful images for image processing by using digital signals while transmitting video signals over long distances of about 50 m. Next, we developed the "Monocular Stereo Camera System," a sensor equipped with two omnidirectional hyperbolic mirrors capable of shooting 360° horizontally and capable of obtaining distance information of a 360° horizontal structure from the parallax of two panoramic images. In addition, we developed map generation by Visual-Simultaneous Localization and Mapping (Visual-SLAM) using images of Monocular Stereo Camera and map generation technology that superimposes the above distance information. Using the above developed technology, we propose an environment recognition technology for robots to move autonomously in a high-dose environment.