Remote-Controlled Inspection Robot for Nuclear Facilities in Underwater Environment

A remote-controlled inspection robot for nuclear facilities was developed. This is a underwater robot technology combined with inspection and flaw removal technologies. This report will describe the structure and performance of this robot. The inspection robot consists of two parts. The one is driving equipment, and the other is inspection and grinding units. It can swim in the tank, move around the tank wall, and stay on the inspection area. After that it starts inspection and flaw removal with a special grinding wheel. This technology had been developed to inspect some Radioactive Waste (RW) tanks in operating nuclear power plants. There are many RW tanks in these plants, which human workers can be hard to access because of a high level dose. This technology is too useful for inspection works of human-inaccessible areas. And also, in conventional inspection process, some worker go into the tank and set up scaffolding after full drainage and decontamination. It spends too much time for these preparations. If tank inspection and flaw removal can be performed in underwater, the outage period will be reduced. Remote-controlled process can be performed in underwater. This is the great advantage for plant owners. Since 1999 we have been applying this inspection robot to operating nuclear 11 facilities in Japan.