Abstract: An apparatus for the inspection of a nuclear reactor fuel assembly in a water-filled pool having fuel rods with spaces therebetween includes an encapsulated housing having walls and being disposed in the water-filled pool. A lever drive mechanism is disposed in the housing. A rotary transmission connected to the lever drive mechanism extends through one of the walls of the housing toward the surface of water in the pool. A plurality of stationarily disposed lever linkages jut out from the rotary transmission outside the housing. Each of the lever linkages has an end facing away from the rotary transmission. Carriers are each connected to a respective one of the ends of the lever linkages. Probes are each disposed on a respective one of the carriers. Ultrasonic test heads are each disposed on a respective one of the probes for insertion into the spaces between the fuel rods.

Abstract: An apparatus for the inspection of nuclear reactor fuel rods combined in fuel rod clusters with spaces therebetween in a fuel assembly includes test probes each being disposed at a different respective level along the fuel assembly. Fingers are each part of a respective one of the test probes. Ultrasonic test heads are each disposed on a respective one of the fingers. The test heads are inserted into the spaces between the fuel rods, and the insertion position of each of the test probes is corrected independently of the insertion position of the others of the test probes, before insertion of the test probes.

Abstract: A method for checking the dimensions of a fuel assembly for nuclear reactors formed of a bundle of longitudinally extended fuel rods disposed in rows in a water tank defining gaps between the rows includes moving two mutually parallel probes with respective ultrasonic test heads at free ends thereof relative to the fuel assembly, inserting the probes laterally into the gaps between the fuel rods accommodating a row of fuel rods between the probes, transmitting ultrasonic waves with one of the ultrasonic test heads, receiving the ultrasonic waves with the other ultrasonic test head, continuing irradiation during the movement of the probe, determining at least one of the height and width of a peak of the ultrasonic waves associated with a water path between the transmitting and receiving test heads, and using at least one of the height and width of the peak to determine the spacing between two fuel rods.

Abstract: A method for checking the dimensions of a nuclear reactor fuel assembly in a water tank uses two mutually parallel probes each having a first probe side carrying an ultrasonic test head at a free end thereof with acoustic directions directed towards each other and each having a second probe side facing away from the ultrasonic test head. The acoustic waves are transmitted with one of the ultrasonic test heads, the transmitted acoustic waves are received with the other ultrasonic test head, one of the second probe sides is brought into contact with a given region of the fuel assembly to be checked, the probes are moved towards each other in the direction of the acoustic waves due to contact pressure with the fuel assembly, the probe movement is indicated and assessed by a reduction of transit time of the acoustic waves between the test heads, and the actual dimension of the fuel assembly region to be checked is derived while accounting for the dimension of probe movement.

Abstract: A method for testing vertically disposed fuel rods combined in fuel rod clusters or fuel assemblies in rack positions of a fuel assembly rack of a water-cooled nuclear reactor includes inserting a holding device into first and second unoccupied rack positions while maintaining an unoccupied third rack position therebetween, inserting a fuel assembly to be tested into the third rack position with a lifting device, locking the fuel assembly to the holding device while the fuel assembly is in the third rack position, moving the fuel assembly vertically upward with the holding device, interrupting the upward motion of the fuel assembly, subsequently inserting a probe with a test device into spaces between the fuel rods in a testing operation, moving the fuel assembly vertically downward with the holding device after completing the testing operation until the fuel assembly is deposited in the third rack position, removing the fuel assembly with the lifting device, and depositing another fuel assembly to be tested

Abstract: A device for the inspection of fuel rods combined into fuel rod bundles in a fuel element of a nuclear reactor includes a frame for supporting a fuel element including a base plate, a cover plate and four supports in the form of four first leadscrew drive mechanisms, two mutually parallel second leadscrew drive mechanisms attached to and extending transversely to the first leadscrew drive mechanism, a third leadscrew drive mechanism jointly supported by and extending transversely to the second leadscrew drive mechanism, and an accessory carrier mechanism disposed on the third leadscrew drive mechanism and movable in a plurality of levels for entering gaps between fuel rods of the fuel element.

Abstract: A method for locating defective fuel rod cladding tubes of a water-cooled nuclear reactor within fuel rod bundles combined to form complete fuel assemblies disposed in a water-filled fuel assembly storage pit, including a mooring, a carriage disposed on the mooring, a manipulator disposed on the carriage and having a water proof space disposed therein, driving elements of the manipulator disposed in the water proof space, probes disposed directly in the water of the pit and connected to the driving elements, at least one ultrasonic test head disposed on each of the probes, and a lifting device for holding the fuel assemblies, includes: centering a fuel assembly to be tested on the mooring with the lifting device, moving the carriage into a test position, and transmitting motion cycles of the driving elements in the water proof space to the probes in the water of the pit for moving the probes and the test heads between the cladding tubes, and a device for carrying out the method.

Abstract: An apparatus for inspecting fuel assemblies, includes a water container, a receptacle disposed in the container for securing bases of fuel assemblies vertically disposed in said container, a beam, a plurality of fingers engaged by the beam, measuring probes supported on the fingers, and a guiding device disposed in the container and accurately positioned relative to the receptacle for guiding the beam laterally toward the fuel assemblies for inserting the measuring probes in a given direction into spaces between cladding tubes of fuel rods of the fuel assemblies, each of the fingers being movable relative to the given insertion direction after striking an obstacle.

Abstract: The invention relates to a method for testing fuel element tubes by ultrasonic energy. For testing, each tube becomes disposed in the space between a transmit transducer and a receive transducer. The echo signals falling within a predetermined time interval are evaluated. Since the distance between the transducers may vary as the transducers move through the space between fuel element tubes, the transmitted signal reaching the receive transducer without passing through the tube may be confused with the revolving echo signal. Therefore, this invention discloses an arrangement for cyclically controlling the setting of the time gate before each such tube is in position between the transducers. To this end, the ultrasonic transit time of signals between the transmit transducer and the receive transducer is measured in the gap between the last tested tube and the next to be tested tube.