Remote-Controlled Inspection Robot for Nuclear Facilities in Underwater Environment

Abstract

A remote-controlled inspection robot for nuclear facilities in underwater environment was developed. The Array system of Eddy Current Testing (Array-ECT) is installed on the existing robot that consists of the driving unit and the inspection unit with enlarged Charge-Coupled Device (CCD) camera. It can swim in the tank, crawl on the inner surface of the tank, stay on the inspection area and by its two devices, Array-ECT and enlarged CCD camera, start inspection. Array-ECT can record the color contour image, and also can display oscillograph. This technology had been developed in order to reduce worker’s radiation exposure and improve inspection-ability in nuclear power plants for some Radioactive Waste (RW) tanks. With conventional manual inspection, RW tanks must be examined with the sequence of (a) full drainage and decontamination, (b) scaffolding set-up with workers under high dose, and (c) manual inspection. As such, the inspection is time consuming and workers should have high radiation exposure. With the original robot that has only enlarged CCD camera, inspection can be performed without tank drainage and with minimum worker’s radiation exposure. However, it needs experienced inspector for interpretation of visual examination using enlarged CCD camera. Newly developed robot with Array-ECT and enlarged CCD camera can achieve the same performance using the original robot and an experienced inspector for visual inspection using enlarged CCD camera. The new feature added to the original design (i.e. Array-ECT) eliminates the need for an experienced inspector.