ACM-R4.3, a modified version of the versatile inspection robot ACM-R4.2, was used in March 2017 at the No.1 Fukushima Nuclear Power Plant. It consists of a slender and articulated snake-like robot with active wheels for motion on narrow and uneven spaces.



ACM-R4.3 was equipped with a high-resolution camera in front, and a navigation camera in the back. Due to its small dimensions, it was able to move among the debris of the damaged reactor building, acquiring pictures and videos with an unprecedented level of detail.



The robot was able to navigate and reach places where no humans can go now, such as the edges of the spent fuel pool and the top lids of the reactor core. The data acquired with ACM-R4.3 is being used to analyze the structural conditions of the building and to plan the next steps of the decomissioning efforts.