Abstract: A teleoperated tracked vehicle for inspecting the inner wall of a RFX machine is presented in this paper. It must enter the toroidal chamber of the machine and check the condition of the graphite tiles using a vision system based on a CCD camera. The design of the vehicle has taken into account many requirements imposed by the critical environmental conditions. The encumbrances problems have been faced and solved by off-line simulating the vehicle motion by means of a robotic simulator integrated with a CAD system. The insertion of the vehicle through a port of the chamber has also been off-line simulated in a virtual environment, in order to solve many of the related problems during the design phase.