Abstract: In order to carry out interventions, particularly for inspection and maintenance purposes, within heat exchangers, such as the steam generators equipping nuclear power stations, a device is proposed, which has an articulated arm formed from at least two rigid segments (24a, 24b), which are articulated to one another about an axis (A), as well as two plates (30a, 30b) mounted at the ends of the articulated arm via two handles (28a, 28b), each authorizing two rotations about two orthogonal axes (B, C), whereof one (B) is parallel to axis (A) and the other (C) is perpendicular to the surface (31a, 31b) of the corresponding plate. Each plate (30a, 30b) carries fastening members (32) able to engage in perforations (20a) of a tube plate (12) of the exchanger, as well as a support (34) for an intervention tool.

Abstract: A circuit for the rapid calculation of the real and imaginary parts of the h first harmonics of a signal supplied by a measuring device and particularly for the analysis of the voltage supplied by a non-destructive eddy current testing probe. The circuit comprises an analog-digital converter, a random access memory, and calculating means comprising a PROM, a counter, a multiplier, an accumulator and a sequencer.

Abstract: A device for positioning a member so as to face each of a plurality of perforations arranged in a given grid in a plate, especially for the inspection of the tubes of a steam generator in a nuclear power station. It comprises a body having at least two attachment members for fastening the device in the perforations. The device is rotatable around one or the other of these attachment members so as to displace it on the plate, and has a support carrying the member and pivotable with respect to the body in order to bring the member into a position facing several perforations without displacing the device.

Abstract: Eddy current non-destructive testing device comprising in per se known manner an exciting generator, a probe connected to the latter, means for sampling in the probe a measuring voltage, means for producing a reference voltage, a differential amplifier having a first and second input and an output, a first input receiving the measuring voltage and the second the reference voltage, digital signal processing means having an input connected to the output of the differential amplifier across an amplifier, said processing means successively comprising an analog--digital converter, a first random access memory and a digital processing circuit, wherein the means for producing a reference voltage comprise a second random access memory having an input and an output, the input being connected to the output of the first random access memory across a switching circuit and a digital--analog converter having an input connected to the output of the memory and an output connected to the second input of the differential ampli

Abstract: Supply circuit for an eddy current probe with two windings, comprising two parallel supply channels connected to the probe by a cable, each channel incorporating a reference winding and an amplification circuit having an input and an output, one of the ends of the reference winding being connected to the output of the amplification circuit and the other to the input of said circuit via a negative feedback resistor, wherein the amplification circuit of each channel comprises a first amplifier having an input constituting an input of the amplification circuit and an output connected to an absolute measurement access, a first resistor, whereof one end is connected to the output of the first amplifier, a second amplifier having an input connected to the other end of the first resistor and an output constituting the output of the amplification circuit, and a second resistor connected between the output and the input of the second amplifier.

Abstract: The present invention relates to a device for introducing a mobile positioning body onto a tube plate of a steam generator through a manhole.The device comprises two substantially parallel rails essentially shaped like a curved angle plate, whereby a trolley can slide along the rails and on which can be placed the said moving body. During the introduction of the moving body, the device is provisionally fixed to the tube plate by lugs and to the inner face of the manhole by a pedal maintained in place by a spring.Application to the inspection of steam generator tubes.

Abstract: Apparatus for checking the tubes of a heat exchanger in an area spaced by a given distance from the end of said tubes, by means of a probe performing a helical movement, wherein the apparatus comprises a threaded rod, which can be screwed into a nut carried by a positioning and supporting device suspended on the exchanger tubes, first flexible means, which are perfectly rigid in torsion and of constant length ensuring the integral transmission of a rotation torque between the threaded rod and the probe, second flexible means ensuring the integral transmission of said rotation torque between the rotation control means and the threaded rod, a flexible sheath connecting the nut and a fixed chassis external of the exchanger, and means for sliding the assembly constituted by the probe, the first flexible means, the threaded rod and the second flexible means between a rest position in which the probe is placed in the said nut and an inspection position in which the threaded rod engages in the nut.