Abstract: Detensioning of expanded tubes is brought by way of an installation using a rotopeening method. The tool is constituted by a cage moved along a helical path centered on the axis of the tube to be treated. The cage supports in rotary manner a shaft, whose axis is parallel and offcentered with respect to that of the cage. The shaft carries flexible plates, called brushes, whose ends are equipped with shot able to peen the inner wall of the tube during the rotation of the shaft. The helical path ensures a regular distribution of the impacts and consequently a uniform treatment of the surface.

Abstract: The device comprises at least two ultrasonic transducers emitting focused radiation and a circuit making it possible to measure the difference between the sampled signals supplied by these two transducers. This difference is cancelled out when the probe faces the object.Application to metrology and the position control of objects.

Abstract: The fault-containing area to be inspected is insonified by means of an ultrasonic transducer with a space-limited beam which is displaced in stepwise manner, the signals coming from the successively insonified areas being detected by several receivers, the phases and amplitudes of the signals being determined and the reconstitution of the area to be inspected performed. There is a main image of the fault and also parasitic images thereof. The number of receivers is chosen in such a way that the distance between the parasitic images and the main image exceeds the width of the area insonified by the transmitter and the reconstitution is only carried out in the insonified areas having given rise to a signal in order to eliminate the parasitic images. Application to the non-destructive inspection of mechanical parts.

Abstract: A multitransducer ultrasonic probe having transducers of different sizes for the nondestructive testing of mechanical parts. The probe has at least one line of M transmitter and/or receiver ultrasonic transducers, a control unit for the activation of at least one group of m juxtaposed transducers, selected from the M transducers and for the displacement of the activated portion of the probe after each activation. The M transducers all have different sizes and are arranged in monotonic manner in accordance with their sizes, the sizes being determined so as to scan an object to be inspected with a redundancy rate which is independent of the depth of the locus to be inspected.

Abstract: Process and apparatus for examining a fuel assembly of a nuclear reactor. The apparatus includes a support on which is positioned the assembly to be examined, a wave transmitting source directed towards the assembly to be examined, a mechanism for examining the assembly receiving the waves transmitted by the source and which have been reflected by the assembly. The examining mechanism includes a spindle directed towards a mirror, which is inclined in such a way that it reflects the waves reflected by the assembly towards the examining mechanism, and a device for providing protection against radiation emitted by the assembly, the device being positioned between the assembly and the examining mechanism.

Abstract: A vehicle able to move between two walls and particularly in the space between two vessels of a fast neutron reactor, for inspection and testing; the vehicle having two wheels bearing on one of the two walls and connected to the vehicle body by two longitudinal arms and two wheels bearing on the other wall and arranged symmetrically with respect to the previously mentioned wheels and connected to the vehicle body by two transverse arms. The longitudinal and transverse arms may be folded back to permit the passage of the assembly through an opening.

Abstract: 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.

Abstract: An apparatus for sending a sensor, such as an eddy current sensor, into a condenser, heat exchanger or steam generator tube. The apparatus first sends the sensor, which is attached to a cable, into the tube by means of a pressurized fluid which pushes the sensor along tube interior. At the extreme of the sensor's travel into the tube, a first ferrule attached to the rear of the cable blocks a first hydraulic passage in the apparatus. By virtue of slidable control pistons in the apparatus, this blocking cuts off the pushing pressure behind the sensor and then causes wheels to frictionally engage the cable to pull the sensor back to its starting position. At this time, another ferrule, carried near the sensor end of the cable, blocks a second hydraulic passage to thereby disengage the wheels from the cable. The cycle of (1) sensor pushed into the tube (2) sensor withdrawn from the tube, is now complete.

Abstract: A circuit for automatically correcting a signal given by a differential pick-up. Said circuit comprises as many corrective channels as there are frequencies in the signal. Each of said channels, comprises a band-pass filter centered to the frequency ascribed to the respective channel, an analyzer for the resistive (X) and reactive (Y) portions of the filtered voltage, two stages for the separate treatment of said two portions, each of said stages comprising a threshold comparator, a counter, a digital-analog converter, and a multiplier for multiplying by a reference-signal, either in phase (as regards portion X), or in phase-quadrature (as regards portion Y), with respect to the pick-up energization. An adder is adapted to reconstitute a corrective voltage to be substracted from the input signal.

Abstract: An ultrasonic centering apparatus, wherein it comprises at least one ultrasonic transducer placed within an enclosure, said transducer transmitting at least one ultrasonic wave, means for collecting the different ultrasonic echos from the walls of said enclosure, means for measuring the time gap separating the reception of the different echos and means for displacing the transducer or transducers until the different echos are received at the same time by said echo receiving means.A particular application of the invention is to the centering of inspection equipment in the tubes of nuclear reactor vessels.

Abstract: Measuring bridge for a device for inspecting or checking by eddy currents of the type comprising a first pair of adjacent branches each constituted by a resistor and a second pair of adjacent branches in parallel with the first pair, whereof at least one of the branches is constituted by a winding which is sensitive to the faults of the part to be inspected, characterized in that it comprises a supplementary resistor connected in parallel on the said winding.

Abstract: A pneumatic drive device for a probe, more particularly for an eddy current measuring probe has a tight flexible tube in which the probe is movably mounted with a cable connected to the probe. A cable pushing and pulling device is connected to one end of the flexible tube and a compressed fluid is introduced into the flexible tube for driving the probe towards and then into the tube to be checked. A tight connection for the other end of the flexible tube to the tube to be checked is provided including a cylinder-piston-restoring spring assembly engaging the drive device beneath a tube to be checked and then disengaging the drive device from the tube which has been checked.

Abstract: A self-propelled carriage for inspecting the primary vessel of a fast reactor is capable of displacement within the interspace between the primary vessel and the containment vessel in order to inspect and test any predetermined zone of the primary vessel, the carriage being associated with a drive mechanism and applied against the oppositely-facing wall of the containment vessel. The carriage is suspended from a composite cable actuated by a handling apparatus for introducing the carriage into the interspace and withdrawing it therefrom. The composite cable supplies electric power as well as the different fluids required for positioning and operation of the inspection devices which are mounted on the carriage.

Abstract: In a focusing ultrasonic system for detecting flaws in a part and obtaining a single focal point in the ambient medium, the ratio of the distances between the points of impact of the different rays of the ultrasonic beam on the separation surface of the part to the two focal points of the beam along two orthogonal planes as considered in the ambient medium is equal to: ##EQU1## WHERE I.sub.1 IS THE ANGLE OF INCIDENCE OF A RAY AND I.sub.2 IS ITS ANGLE OF REFRACTION.