Most of the long-reach inspection devices developed so far have a limitation in the reduction of their diameter when their length is increased. This limitation is due to the technology used to provide the actuation to the system. The use of water-jet as propulsion source is promising to be a solution for this problem. Currently different devices use water-jet as propulsion. However, none of these systems have been designed for small-scale nor have a straightforward control. Therefore, in this paper, we discuss the development of a long-reach water-jet probe aimed to be used in Fukushima Daiichi Nuclear Power Plant. The main elements that define this probe are three high-pressure pumps at the base, three hoses whose water flow is controlled for maneuvering the device, an Inertial Measurement Unit to acquire the attitude of the tip, and a joystick that allows the user the control of the whole device. Moreover, its design allows it to move in different kind of environments and generate three-dimensional motion. Besides the experimentation developed to characterize its behavior, the system was tested in different environments; such as on the ground, in the air and inside the water; showing the best control in aquatic environments.

Long-reach robots offer good performance developing tasks in areas where the access is difficult or dangerous. Due to their multiple degrees of freedom, they are able to adapt easily to different environments. These robots base their locomotion to two different elements: tendon cables or fluid pressure elements. Normally these robots are divided in sections and each section has its independent degrees of freedom. Therefore, if the length of the robot increases, the number of sections increases as well. This also means an increment in the diameter for each section and a more complex control for the whole system. In this paper we introduce the concept of a novel water-jet long-reach robot, which allows increasing the length of the robot without affect its number of elements, control complexity and diameter. Due to its characteristics, it is possible to use this robot in different environments, confined or opened spaces. We test the performance of the first prototype in different scenarios in order to validate our concept.

After the incident in Fukushima nuclear plant, the access to several critical areas was damaged. Thus, the monitoring of them turned difficult. In order to keep tracking the status of these areas, it has been proposed to insert sensors through piping that is located nearby the element of interest. However, these pipelines have many restriction, like small diameter, changes of direction, elements that block access, etc. and none of the existing technologies have the capability of going through the piping while carrying the required sensors. In this paper we report a proposal of a new system, whose propulsion is based on water-jet. This device shows good possibilities to fulfill the requirements of carrying out the desired task. The design of this proposal aims to solve the limitations observed in the experiments done with a current technology, which are also described briefly. Basic tests done with the prototype developed are shown as well.

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