Abstract: A hollow plug for blocking a heat exchanger tube includes an expansion zone expanded into a frictional connection with the heat exchanger tube. An outer surface in the expansion zone has a first part with a relatively greater surface hardness and a second part with a relatively lesser surface hardness. The first part has a greater surface hardness than the heat exchanger tube. The second part has a lesser surface hardness than the heat exchanger tube. The first part also has a relief pattern.

Abstract: A device for irradiating an object, includes a source mount, a source disposed on the source mount for generating thermal neutron rays, a moderator surrounding the source, a collimator having a ray inlet side with an inner surface and at least one funnel-shaped collimator duct for the neutron rays opening toward an object, a neutron-permeable wall separating the source mount from the ray inlet side of the collimator defining a space between the wall and the ray inlet side with an inner peripheral surface of the space, and a plastic plating disposed on the inner peripheral surface of the space and on the inner surface of the ray inlet side defining an opening of the at least one collimator duct free of the plastic plating.

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: 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: Method and apparatus for assisting the loading of a reactor core with new and/or irradiated elongated fuel assemblies which includes inserting a fuel assembly with a fuel assembly carrier from a storage pit into a grid position of a reactor core with a refueling machine having propelling equipment, supplying an actual position of the fuel assembly carrier to the propelling equipment of the refueling machine during movement of the refueling machine between the storage pit and the reactor vessel, comparing the actual position of the fuel assembly carrier with a desired position of the fuel assembly carrier to find a deviation, and carrying out a correction of the deviation in the travelling movement of the refueling machine based upon the comparison.

Abstract: A method and apparatus for simulating operational demands acting an expanded tube joints includes penetrating a central inner region of a circular disc of a test body with a plurality of hollow cylinders. Sleeves or hollow plugs are connected to the hollow cylinders in the vicinity of the disc. A stress condition is created in the inner region corresponding to the operational demands by applying a force in an outer region of the disc through a uniform introduction of heat in the outer region while cooling the inner region. Outer hollow cylinders may serve as cooling passages and may form a boundary between the inner region and the outer region. Thermal insulation may be associated with the outer region. An electric resistance heater may be associated with the outer region for applying the force.

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: An apparatus for viewing a foil irradiated in the course of neutron radiography, the foil having nuclear tracks being visible after etching under the action of light, includes a completely enclosed housing having a first surface with an opening formed therein for receiving an etched foil, a second surface opposite the opening, a black coating disposed on the second surface, and at least one light source disposed between the black coated second surface and the opening for transmitting light rays striking the foil in the opening at an angle deviating from the normal.

Abstract: A device for the generation of thermal neutrons includes a gas-filled housing having a wall with inner surfaces and a neutron outlet opening, a spherical moderator housing disposed in the gas-filled housing, a transportable neutron source disposed in the spherical moderator housing, and cups formed of moderating material disposed between the moderator housing and the inner surface of the wall of the gas-filled housing, the cups being spaced at a given distance from the inner surface of the wall of the housing, from the moderator housing and from each other defining spaces between the cups, and the spaces between the cups defining openings directed toward the neutron outlet opening.

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 clamping element for fixation in a bore of a structural element and for carrying a load includes a clamping sleeve formed of a plurality of partial shells and having a central axis, a clamping bolt vertically movable in the clamping sleeve, the partial shells and the clamping bolt having mutually cooperating spreading surfaces converging and tapering toward the load, the clamping bolt permanently subjecting the partial shells to an automatically acting clamping force, the clamping bolt being axially movable to counteract and relieve the clamping force, the partial shells and the clamping bolt having surfaces adjacent the spreading surfaces converging obliquely toward the central axis and forcing the partial shells into a disengaged position.

Abstract: A steam generator having a tube sheet, tubes ending in the tube sheet, a chamber adjoining the tube sheet having an access opening formed therein and a device disposed in the chamber for inserting a sleeve into one of the tubes in a plurality of partial insertion strokes, the inserting device includes a movable clamping device holding and moving the sleeve in axial direction of the tube in one of the partial insertion strokes, and a stationary clamping device associated with the movable clamping device holding the sleeve during a backstroke of the movable clamping device.

Abstract: A crash protection apparatus for a pulling device having a hollow piston cylinder and a pulling claw for pulling a tube out of a tube sheet of a heat exchanger chamber in which the pulling device is disposed, the crash protection apparatus includes another cylinder without a piston rod having an axis substantially parallel to the axis of the hollow-piston cylinder and being fixed relative to the tube sheet in the chamber, a piston of the other cylinder, a bracket extending from the piston substantially at a right angle to the axis of the other cylinder for supporting the pulling device with a supporting force provided by the other cylinder, and a device for controlling the supporting force for compensating only the weight of the pulling device in each position of the pulling device.

Abstract: Neutron absorber rods are mounted with their upper ends in bores formed in a mounting device and the absorber rods are movable within guide tubes of a nuclear reactor fuel assembly. A holding device is firmly attached to a fixed location of the storage pit. The holding device has holder tubes for absorber rods. In order to replace the absorber rods, the mounting device with the neutron absorber rods is placed and locked in the holding device, the mounting device is disconnected from at least one neutron absorber rod to be replaced, the mounting device with any neutron absorber rods still attached to it is removed from the holding device, the disconnected neutron absorber rods remaining in holder tubes of the holding device are removed for storage, new neutron absorber rods are placed in the empty holder tubes and the mounting device with any neutron absorber rods still connected to it are placed in the holding device and the mounting device is connected to the new neutron absorber rods.

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: Device for inspection and repair of tubes of a nuclear reactor steam generator in a tube bundle being disposed in a tube sheet and opening into at least one chamber having an opening formed therein, including a manipulator being insertible in the chamber through the opening and being lockable to the tube sheet for carrying remotely controlled and monitored inspection instruments and tools, the manipulator including a support leg being adjustable in length in the axial direction, a main arm being connected to and movable relative to the support leg, and an equipment carrier being connected to the main arm and movable relative to and together with the main arm, and a mounting rod being connectible to and detachable from the manipulator.

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: A method of determining with improved accuracy, the temperature margin to saturation of a heated pressurized liquid or vapor contained in a closed system. This method is characterized by the utilization of a direct measurement of the pressure margin to saturation instead of a measurement of the actual pressure of the system. The actual temperature of the system is used to determine the appropriate portion of the saturation curve to be used for the conversion of the pressure margin to saturation to the temperature margin to saturation.

Abstract: A steam generator having a steam generator chamber, a tube plate bordering the chamber, tubes terminating in the tube plate being accessible through the steam generator chamber, a tubular column in the steam generator chamber having an end facing toward the tube plate, and a swivel arm extended from the tubular column being movable parallel to the tube plate for carrying a device for testing and/or repairing the steam generator tubes, includes a clamping element for positioning the tubular column relative to a tube of the tube plate, and a coupling being detachable from outside the steam generator chamber connecting the clamping element to the tubular column, the clamping element including a drive element disposed in the tubular column, an expansion plunger connected to the drive element for axially inserting the expansion plunger partially into a tube, an expansion sleeve formed of separate clamping jaws for engaging the tubes, the clamping jaws having ends being insertible into a tube, and a holding element