A tool is essentially an extensible mechanical arm adapted on one end to support equipment in a hostile environment while the arm is manually manipulated from its second end in a benign environment. The arm is pivoted at the entrance to an area containing nuclear radiation with its end projected into the radiation area, and adapted to install and remove equipment.

A device for positioning a member, such as a guide tube, so as to face the perforations of a plate. The device comprises a remotely fitted attachment finger, using for this purpose e.g. a pole onto which is threaded the remainder of the device. A remotely controlled locking system makes it possible to fix the two parts, each incorporating at least one attachment member and which can be fixed in a perforation. These displacements of the device, following the fitting thereof, are also remotely controlled. The device can be applied, to the inspection of the tubes of a steam generator of a nuclear power station by means of an eddy current probe or sensor.

A tool carrier unit, intended to be moved over a tube plate, comprises two perpendicular arms equipped with devices for engaging in the holes of the plate, and for moving the unit, step by step, by relative movement of the arms, across the plate. The unit comprises a supporting element in the form of an angle bracket defining a vee arranged with its apex perpendicular to the plate. The arms are arranged external to the vee, and at the inside of the vee, unaffected by the movement of the arms, guides are provided for supporting a tool.

A vehicle of the invention comprises at least two transfer arms including means for causing expansible positioning fingers to penetrate into the tubes of a steam generator and for extracting said fingers from said tubes. The vehicle also includes at least two pivoting fastening heads which contain said expansible positioning fingers. The heads are interconnected by one of the telescopic transfer arms, which arms extend perpendicularly to said pivoting heads. The other telescopic transfer arm is fixed to one of the heads and it extends perpendicularly therefrom with its opposite end carrying a tool support. Such a vehicle is particularly suitable for inspecting and maintaining tubes in tube apparatuses, e.g. the steam generators of pressurized water nuclear reactors.

A "finger walker" apparatus for remotely traversing a flat surface having a regular array of openings, such as the tube sheet of a nuclear steam generator. The apparatus has a rectangular base having four base fingers disposed in a rectangular pattern for engagement with the openings. An annular platform surrounds the base and is rotatable about the base. The base is adapted to move linearly a pitch multiple within the platform. Fingers on the platform are adapted for engagement with the openings. The apparatus can orient itself for movement in one of many directions by engaging the platform fingers, disengaging the base fingers and rotating the base until the axis of the base is aligned with the intended direction of travel. The apparatus then advances by alternatingly engaging and disengaging the base and platform fingers in coordination with the base and platform moving linearly relative to each other.