Abstract: A process is provided for chemically decontaminating the surface of a metallic component. In a first treatment step, an oxide layer formed on the component by corrosion of the material of the component is detached from the surface of the component with a first aqueous treatment solution containing an organic decontamination acid. In a subsequent second treatment step, the surface which is at least partially freed of the oxide layer is treated with an aqueous solution containing an active component for removing particles which adhere to the surface. The active component is formed of at least one anionic surfactant from the group including sulphonic acids, phosphonic acids, carboxylic acids and salts of those acids.

Abstract: A feeding system for an absorber liquid containing a neutron poison, in particular for a quick shut-down of a nuclear reactor, has a storage container for the absorber liquid and is configured for high operational reliability with simple construction. In particular, a chemical decomposition of the absorber liquid or corrosion of the container wall of the storage container is to be excluded. For this purpose, the storage container is connected to a pressure container via an overflow line, wherein the pressure container is filled with a motive fluid.

Abstract: A fuel assembly for a boiling-water reactor has a water channel and a fuel assembly base, made from a sieve plate and a frame section enclosing the same. The water channel supports a plug with a bore running therethrough, at the lower end thereof, to which the fuel assembly base is fixed. The fuel assembly further comprises an opening through the sieve plate, a skirt, formed on the underside of the plug, surrounding the bore, extending into the opening in the sieve plate, a bush, provided with a first and a second longitudinal section, whereby the first longitudinal section extends from the underside of the sieve plate into the opening in a rotationally-fixed manner and a radial shoulder is provided between the two sections which contacts the underside of the sieve plate. A threaded section of a screw extends through the bush which engages in a thread in the bore in the plug.

Abstract: An end piece for a corrugated hose contains a bushing having a front region and a rear region opposite of a longitudinal direction. The rear region is located inside the hose in a mounted state of the bushing. The front region has a collar forming a groove for receiving the free end of the hose. The rear region has a plurality of flexible tongues, which have a relief direction that is oriented perpendicular to the longitudinal direction of the bushing and directed toward the outer chamber of the bushing. A portion of the flexible tongues contains a radially projecting detent protrusion for implementing an engagement active in the longitudinal direction of the bushing. A retaining sleeve, received by the bushing with precise fit and, in the mounted state of the end piece, extends in an inner chamber enclosed by the bushing, limits the radial play of the flexible tongue.

Abstract: A method of decontaminating an oxide layer-comprising surface of a component or a system of a nuclear facility. An acidic water film is produced on the surface, the film of water is brought into contact with a gaseous acid anhydride, and the oxide layer is treated with gaseous ozone as oxidizing agent.

Abstract: A method to remove deposits containing magnetite and copper from a container, particularly from a steam generator of a nuclear power plant. In a first step, the container is treated using an alkaline cleaning solution containing a complexing agent forming a soluble complex with iron ions, a reducing agent, and an alkalizing agent. In a second step a further complexing agent forming a more stable complex with iron III ions than the complexing agent used in the first step and an oxidant are added to the cleaning solution of the first step present in the container.

Abstract: A method for monitoring the fill level of a liquid in a liquid container, in particular for monitoring the coolant fill level in a reactor pressure vessel of a pressurized water reactor system, wherein a determination is made about the drop in the liquid level below the installed height of a heated thermal element by way of the temperature difference measured between said heated thermal element and an unheated thermal element associated therewith, both of said elements being disposed in the liquid container, said method comprising the especially reliable triggering of an alarm with a short response time while maintaining a low level of physical and controls engineering complexity when the liquid level to be monitored falls below a critical value.

Abstract: An apparatus for measuring the filling level in a liquid vessel, in particular in a reactor vessel of a nuclear-engineering plant, with a plurality of elongate, spaced-apart measurement tubes. Each measurement tube has a number of thermocouples which are distributed in the longitudinal direction. A thermocouple, which acts as a primary signal transmitter, is heated by a heating element and is arranged on a first measurement tube, has assigned to it on the signal side an unheated thermocouple, which acts as a reference signal transmitter and is arranged on a measurement tube which is different from the first measurement tube.

Abstract: A pencil-shaped electrical heating element, in particular for application in a device for measuring filling level in a liquid container, in particular in a reactor chamber of a nuclear plant, contains an electrically-conducting sleeve and at least one electric line embedded therein which is in conducting contact with the sleeve. The electrical line has at least two line sections with differing electrical properties and/or thermal conductivities.

Abstract: In a method for ascertaining the deformation of a fuel assembly in a pressurized-water reactor, the fuel assembly is placed in a measurement station located inside a flooded pool. The measurement station has a holding apparatus for accommodating and fixing the fuel assembly and also a camera which can be moved at least approximately parallel to its bearing axis. Digital images of the fuel assembly are recorded and stored using the camera in various axial positions, in which in each case one selected structural element of the fuel assembly is located, with the position of the fuel assembly in the recorded image depending on the deformation of the fuel assembly. Each recorded image is segmented using methods of digital image processing, and the selected structural element is identified by comparison with a virtual image of the structural element.

Abstract: A feeding system for an absorber liquid containing a neutron poison, in particular for a quick shut-down of a nuclear reactor, has a storage container for the absorber liquid and is configured for high operational reliability with simple construction. In particular, a chemical decomposition of the absorber liquid or corrosion of the container wall of the storage container is to be excluded. For this purpose, the storage container is connected to a pressure container via an overflow line, wherein the pressure container is filled with a motive fluid.

Abstract: A physical-chemical method for cleaning a secondary chamber of a heat exchanger in a nuclear facility, includes drying the secondary chamber and introducing a cleaning solution into the secondary chamber to treat deposits present in the secondary chamber.

Abstract: A safety system for a nuclear plant includes a plurality of catalytic recombiner elements each triggering a recombination reaction with oxygen when hydrogen is entrained in an onflowing gas flow, so that reliable elimination of the hydrogen from the gas mixture is ensured with an especially high degree of operational safety even based on comparatively extreme conditions or scenarios of the aforementioned type. The recombiner elements and/or the flow paths each connecting two recombiner elements on the gas side are configured in such a way that a pressure pulse triggered in the gas medium by an ignition during the recombination reaction in a first recombiner element triggers a gas displacement process having a flow rate of at least 5 m/s in the onflow region of a second, adjacent recombiner element. A nuclear plant with a safety system is also provided.

Abstract: A method is provided for conditioning a waste solution obtained during the wet-chemical cleaning of conventional or nuclear plants and containing organic substances and metals in ionic form. At least a portion of the organic substance is degraded by electrochemical treatment or UV radiation of the waste solution, at least one metal precipitates by the addition of phosphoric acid and a resultant phosphate precipitate is removed from the waste solution.

Abstract: A fuel assembly for a boiling water reactor contains a plurality of fuel rods maintained laterally by spacers and surrounded by a fuel assembly case. The outer walls of a spacer are provided with projecting elements that maintain a minimum space between the outer surface of the spacer and the fuel assembly case, the opening span of a spacer being smaller than the internal width of the fuel assembly case. The fuel assembly is characterized in that the spacer is maintained in an off-center position by a force acting laterally thereon such that an external space located between an outer surface of the spacer associated with the outer surface of a central cell and the fuel assembly case is narrower than an internal gap opposite the external space and oriented towards the center or towards a control element disposed at the center.

Abstract: A technical installation, especially a nuclear power plant, has a number of system components that are respectively supported by a number of beams, and a number of pressurized conduits. The technical installation is designed in such a way that secondary damage occurring in the surroundings of pressurized conduits are kept particularly low even if the pressurized conduits rupture. This is achieved in that at least one of the beams is embodied in a segmented manner in an area that is expected to be affected if a pressurized conduit ruptures, adjacent segments preferably being connected to each other via screw connections.

Abstract: A method for conditioning a cleaning solution resulting from the wet chemical cleaning of a nuclear steam generator, includes electrolytically treating the cleaning solution and depositing radioactive metal nuclides contained in the cleaning solution on a cathode.

Abstract: A method for conditioning a contaminated ion exchange resin includes mixing the contaminated ion exchange resin with water and at least partly breaking up the contaminated ion exchange resin into water-soluble components or fragments through the use of an oxidizing agent added to the water. A resulting aqueous solution is consolidated with a binder, optionally after concentration by evaporation of water.

Abstract: A collecting conduit for leakage monitoring and leakage location at an installation, includes a support pipe having openings. An outer surface of the support pipe is covered by a layer being permeable to a substance to be monitored, at least on a segment extending in longitudinal direction of the support pipe. An electrically conductive layer extends in longitudinal direction. The substance (L) can at least penetrate into the electrically conductive layer and the electrically conductive layer has an ohmic resistance dependent on the substance penetrating into it. An apparatus and a method for leakage monitoring and leakage location are also provided.

Abstract: A method and device for cleaning pipes of a heat exchanger includes placing a throttle-free jet nozzle against an end of a pipe. The throttle-free jet nozzle has an outlet opening of a same size or slightly smaller than an inner cross-sectional area of the pipe. A stream of air containing an abrasive is blown through the pipe for cleaning the pipe.