Abstract: A method and a device are provided for monitoring a power rise during startup of a nuclear reactor (diversitary excursion monitoring). In order to be able to shut down the reactor during startup in the event of prompt critical states, a power band situated in a lower measuring range is prescribed for a signal of power range channels which detects the reactor power in the power range. Startup is continued only when the signal does not exceed an upper limit within a minimum time, after the last occasion of exceeding a lower limit of the power band.

Abstract: A method of welding two work pieces that define a connecting zone between them is described. A friction pin is fed at a starting point into the connecting zone and into opposite regions of the work pieces on both sides of the connecting zone. The friction pin is moved in a welding direction along the connecting zone resulting in the work pieces being welded. The friction pin is led out of the connecting zone after welding the work pieces. The friction pin is fed into a sacrificial element while lifting the friction pin.

Abstract: In a boiling water fuel assembly, some of the fuel rods are shortened. It is necessary to establish a sufficiently high maximum power for transition to boiling. To optimize this power, spacers are at a constant distance at a bottom and are at a shorter distance at a top. The spacers belonging to upper group have turbulence-generating vanes which, however, do not project above the shortened fuel rods.

Abstract: For the redistribution of a coolant flow from a first region into a second region, in particular in boiling-water-reactor fuel elements having an eccentrically disposed water passage, a fuel-rod bundle is constructed in a mirror symmetry manner relative to a diagonal. A distance between adjacent fuel rods increases monotonically in particular along a diagonal. In addition, a fuel-rod bundle as an entity may be offset eccentrically along the diagonal. To compensate for asymmetry in the reactor core, a redistribution of coolant is provided which is advantageous in pressurized-water-reactor fuel elements.

Abstract: A method for inspecting an irradiated fuel element in a nuclear power plant includes the step of measuring, with a measuring device, a spacer of a fuel element for providing measurements of the spacer. The measuring device also measures a calibration rod for providing measurements of the calibration rod, the calibration rod having known dimensions. The measurements of the spacer are calibrated by using the measurements of the calibration rod. It is possible thereby to measure at least the maximum width of the spacer with a measuring error of less than 20 &mgr;m. A device for inspecting an irradiated fuel element in a nuclear power plant is also provided.

Abstract: A hydrogen/oxygen reaction is initiated in a catalytic recombination or ignition device. The device has one or more catalyst bodies with a predetermined catalytic surface. Only a small portion of the entire available catalytic surface, preferably less than 5% of the surface, is permanently maintained at a temperature level above ambient temperature. The temperature is raised by introducing energy with a heater. The heated surface portion acts as an initial igniter.

Abstract: A method for decontaminating a surface includes the steps of bringing a surface of a component formed of an unalloyed steel or a low-alloy steel into contact with a solution containing an oxalic acid for dissolving a contaminated layer from the component. Ions of divalent iron in the solution instantly form a protective layer on exposed surfaces. Iron(III) oxalate is converted into iron(II) oxalate and carbon dioxide by irradiation with UV light in order to provide ions of divalent iron. Subsequent to dissolving the contaminated layer, the protective layer is dissolved by lowering the level of the ions of the divalent iron in the solution. The ions of the divalent iron and the substance having caused the contaminated layer are bound to an ion exchange resin.

Abstract: The apparatus checks the functionality of an electrical drive and/or of a mechanical device associated with the electrical drive. The mechanical device may be an accessory or an actuating element. An electrical unit is associated with the drive and/or with the mechanical device. The unit has connections to which a diagnosis module can be connected. A power supply device is provided for the diagnosis module which can be activated via at least one of the connections to the unit, or via an external signal.