Abstract: A twist-proof mechanical connecting assembly includes first and second components. The first component has a recess formed therein with a groove in the form of at least one pocket. A connecting element in the form of a bolt penetrates the first component and is secured to the second component for interconnecting the components. The bolt has a polygonal head including a safety cup embedded in the recess. At least part of the safety cup is outwardly bent into the at least one pocket for locking the safety cup to the first component and securing the connecting element against loosening.

Abstract: A repair device for removing an inner surface layer on a feed-water connector of a reactor pressure vessel received in a reactor housing having an assembly platform with a carriage displaceable thereon transversely to the reactor pressure vessel, the repair device includes centering means located at a lower end of a telescopically extensible upright tube suspended from the carriage for centering the lower end of the upright tube in the pressure vessel, the centering means having at least two outwardly swingable supports and a hydraulic system for swinging the two supports outwardly umbrella-like; a supporting frame for a feed rod also disposed at the lower end of the upright tube, the feed rod being horizontally self-supporting at an end thereof; a drive motor connected to the feed rod for rotating the feed-rod; means located at the self-supporting end of the feed rod for centrally fixing the self-supporting end in the feed-water connector of the reactor pressure vessel; and a horizontally displaceable turnin

Abstract: Tube lane manipulator for the high-pressure blowdown of heat exchangers having tubes being spaced apart by a given pitch forming tube lanes therebetween with tubes on opposite sides and having closeable servicing openings formed therein providing access to the tube lanes, including a car being insertible into the tube lanes through the servicing openings and being movable therein by remote control, a spraying head being supported on the car and having nozzles with orifices for spraying jets of blowdown water in a given direction into spaces between the tubes, suction lines having suction stubs for pumping off accumulated blowdown water, and extendible and retractible clamping feet disposed on the car for clamping the car to the tubes on at least one side of a tube lane along a clamping plane in conformity with the given tube pitch, the nozzles being positioned in spraying positions of a spraying position sequence by the clamping feet clamping the car, the given spraying direction from the orifices of the nozz

Abstract: A method of repairing partly burnt-off fuel elements in a fuel-element pit of a pressurized-water reactor which includes placing a fuel element previously detected as being defective into a holding cage in substantially upright position with the aid of remotely controlled tools, and tipping it over through 180.degree.; removing the then upwardly disposed fuel-element foot from the fuel element so as to expose the ends of the fuel rods received in the fuel element; inspecting the fuel rods, the ends of which are then freely accessible for defects; removing with a fuel-rod exchanging tool those fuel rods at least which are determined to be defective and depositing them in a storage container; and raising replacement rods with the fuel-rod exchanging tool and inserting them into the fuel element without bending stress in exchange for the removed fuel rods.

Abstract: A nuclear reactor plant has a fuel-element storage pit formed in a pit building and a pit adjacent thereto for safely lowering a fuel-element transporting cask therein, the adjacent pit being connected by a spur channel to the storage bit, a barrier separating the storage pit and the pit adjacent thereto, the barrier being at least one-half as high as the vertical length of the fuel-element transporting cask and being connected to the pit building in a manner as to be capable of withstanding at an upper edge thereof a lateral force equal to at least 10% of the maximum weight of the transporting cask.