Abstract: In order to allow a reliable and passive external cooling of a reactor pressure vessel of a boiling water reactor, outside the reactor pressure vessel a differential-pressure measurement pipe is provided and has a first and a second pipe leg which are connected to one another above a critical filling level. The first pipe leg is connected at the height of the critical filling level to the interior of the reactor pressure vessel. In a normal operating state, the differential-pressure measurement pipe is filled completely with water. In the event of the undershooting of the critical filling level, the water flows automatically out of the first pipe leg. As a result, the differential pressure between the two pipe legs rises, the differential pressure being detected by a measurement device via which the flooding of the exterior is then brought about.

Abstract: After a nuclear reactor has been stopped and allowed to cool down following a period of operation, action is taken in a pool of the nuclear reactor on at least one guide tube of the activated upper internal equipment of the nuclear reactor to enlarge (21b, 21c) guide channels (16b, 16c) of the guide tube (8) in at least one continuous guidance zone. The enlargement is preferably performed by machining discontinuous cavities along the length of the guide channel (16b, 16c). Enlargement is preferably performed on the guide tube (8) in place within the upper internal equipment that has been placed on a storage stand in the reactor pool.

Abstract: The invention proposes a zirconium-based alloy also containing, by weight, apart from unavoidable impurities, from 0.02 to 1% of iron having from 0.8% to 2.3% of niobium, less than 2000 ppm of tin, less than 2000 ppm of oxygen, less than 100 ppm of carbon, from 5 to 35 ppm of sulphur and from 0.01% to 0.25% in total of chromium and/or vanadium, the ratio R of the niobium content, less 0.5%, to the iron content, optionally supplemented by the chromium and/or vanadium content.

Abstract: The wall (6) of the water chamber (5) is welded to the tube plate (4) via a connection ring (10) projecting from the tube plate (4). The wall (6) of the water chamber is welded to the tube plate (4) after the bundle of tubes (3) has been secured to the tube plate (4). The connection ring (10) presents a length in the axial direction that is not less than 300 mm and that is preferably about 370 mm.

Abstract: A responsive system for digital signal processing and a method for operation of the responsive system implement computer programs, which are dependent on a respective update status, in data processing units that communicate with one another through a data transmission unit, in order to make the responsive system particularly reliable, even when subject to frequent revision. During each communication, each data processing unit assigns a revision identity characterizing its update status to a signal produced by it. A data processing unit receiving the signal carries out a comparison to determine if the revision identity characterizing the signal matches a revision identity stored for that signal and, if the revision identities match, the signal is processed.

Abstract: A combined laser and infra red sensing camera is located beneath the reactor head in the vicinity of the closure head tube welds by manipulating known robotic device handling the laser which is used to heat a line along the surface thereby generating a thermal wave that propagates over the one to two square inch test area where the increased thermal resistance of cracks and anomalies makes the surface temperature profile gradient greater at a crack or anomaly. An IR camera captures the test area image of interest as the thermal wave propagates across the target inspection area and the image is processed and enhanced to show cracks and other anomalies as a sharp drop in the thermal scan at the point of the crack using known Photo Thermal NDE technology to convert the scan into a pictorial representation of the scanned surface clearly showing any cracks therein. This process is repeated sequentially until the entire circumference of the weld is scanned.

Abstract: An ultra sonic sound measurement is used to determine the thickness of a partial layer in a multi-layered structure with reduced boundary surface reflections. A plurality of transmission pulses are produced on a predetermined point on the structure with the help of an ultra sonic probe head. The resulting echo signals associated with a transmission pulse are recorded digitally as an HP image. A plurality of wall thickness echo periods from different running periods are superimposed in a homologous manner with the aid of a computer program.

Abstract: An electrical lead-through bushing with an internal conductor surrounded by an external conductor, extending together through a flange element, is particularly suitable for a TDR (time domain reflectometry) measuring system in which the fill level in a reactor pressure vessel of a nuclear installation is monitored. The bushing is particularly suitable for use on a vessel wherein comparatively high pressures and/or high temperatures may prevail. For this purpose, a first space region, formed on a first side of the flange element between the internal conductor and the external conductor surrounding it, is sealed off with respect to a second space region, formed on a second side of the flange element by the internal conductor and the external conductor surrounding it, by way of a number of sealing rings.

Abstract: An apparatus for compressing objects includes a base plate, a frame and a ram head guided so as to be displaceable on the frame. Forces may occur in the peripheral direction of the ram head during the compression of bulky objects. The ram head is rotatable relative to the frame in order to reduce the forces introduced into the frame.

Abstract: A nuclear fuel sintered body is produced from a powder which contains at least one fissile heavy metal oxide. During the further treatment of the powder over the course of the process preceding the sintering operation, a dopant that contains at least 100 ppm of an iron oxide compound is added to the powder. The powder is a UO2-containing powder obtained from a dry-chemical conversion process, and if appropriate, a powder which contains further fissile heavy metal oxide (U3O8, PuO2, inter alia). As a result, the sintered body is provided with high plasticity combined, at the same time, with a large grain size. This advantageously reduces an interaction between the nuclear fuel sintered body and a fuel rod cladding tube during an operation of the reactor.

Abstract: The fitting, in particular a safety valve, operates according to the relief principle or according to the loading principle. The fitting is opened and closed by a plurality of control parts. The control parts are connected in series in the control line of the fitting and are each actuated by a control valve. The control parts open the fitting only when all the control parts are in a position which opens the fitting. The fitting closes as soon as even only one of the control parts is in a position which closes the fitting.

Abstract: Particularly simple selection of data in all of the operating phases for a technical installation is achieved according to the invention, in a method for processing data which are user-specifically stored in different data memories. The functional groups for process control and the functional groups for the installation are each assigned to a selection field of a common selection mask. When one of the selection fields is selected, the respective process data relevant to the process control of the installation or installation data relevant to the installation are selected and displayed in a further display level.

Abstract: A method for sizing cracks is disclosed using a combination of depth crack sizing methods to improve crack sizing accuracy for thin walled tubing and tight crack surface openings less than 0.001 inches for cracks of any depth. The tube or plate wall can consist of a single material or multiple metallic electrodeposited or otherwise intimately bonded layers of materials with different magnetic properties and the sizing method comprises known depth sizing methods such as shear wave, time of flight and the selective use of two unique depth sizing methods designated as Mode Converted Signal (MCS) and Full Skip Normalization (FSN) which provide correction factors for the known sizing methods.

Abstract: An electrolysis unit having a plurality of membrane electrolytic cells connected in series suitable for use in a service station for supplying a motor vehicle with hydrogen as fuel. Each of the membrane electrolytic cells has a membrane provided on both sides with an appertaining contacting disk, especially a support mat made up of a large number of metal wires laid over each other and pressed together. In a service station, a gas cleaning unit is installed on the inlet side upstream from such an electrolysis unit.

Abstract: The alloy contains, by weight, less than 0.05% of carbon, from 0.015% to 0.5% of silicon, from 0.4% to 1.4% of manganese, from 28% to 31.5% of chromium, from 8% to 12% of iron, from 2% to 7% of molybdenum, from 0% to 0.75% of aluminium, from 0% to 0.8% of titanium, from 0.6% to 2% in total of niobium and tantalum, the ratio of percentages of niobium plus tantalum and of silicon being at least 4, less than 0.04% of nitrogen, from 0.0008% to 0.0120% of zirconium, from 0.0010% to 0.0100% of boron, less than 0.01% of sulphur, less than 0.020% of phosphorus, less than 0.30% of copper, less than 0.15% of cobalt and less than 0.10% of tungsten, the remainder of the alloy, with the exception of unavoidable impurities of which the total content is at most 0.5%, consisting of nickel. The alloy is used, in particular, for the production of wires for the electro-gas welding of units or components of nuclear reactors and, more particularly, of pressurised water-cooled nuclear reactors.

Abstract: A fuel assembly for a pressurized-water reactor includes fuel rods held in cells of spacers, control rod guide tubes, and a headpiece and a foot piece, by which it is fixed to upper and lower core grids, respectively. A spacer having a first part, which lies on a radially outer side with respect to a longitudinal center axis of the fuel assembly, and a second part, which lies on a radially inner side and is completely surrounded by the first part are included to reduce the size of gaps between fuel assemblies. The second part is formed of Zircaloy. The first part is made of a metallic material, and when compared to the Zircaloy of the second part, has a lower growth in the radial direction, caused by neutron radiation and a higher coefficient of thermal expansion.

Abstract: The invention relates to an inspection probe for an internal wall of a duct, comprising at least one sensor mounted in a support adapted to be moved inside the duct whilst pressing said sensor flat against said internal wall. The support is formed by a shell which is moulded onto the sensor and comprises a body provided with a window for positioning said sensor and means for attaching said sensor flat against the internal wall of the duct, said means being integrally moulded with the body.

Abstract: An apparatus is disclosed for expanding the ends of a sleeve that has previously been installed into a defective section of inaccessibly located soft metal heat exchanger tubing. The sleeve ends are expanded using an apparatus of a plastic bladder connected to a series of connectable sections of sufficient length to reach the ends of the installed sleeve. The expansion is performed by locating the plastic bladder inside the sleeve at one end and hydraulically compressing the plastic bladder and forcing it to expand in diameter as a function of Poisson's ratio to thus expand the sleeve end into the tube.

Abstract: The alloy contains, by weight, less than 0.05% of carbon, from 0.015% to 0.5% of silicon, from 0.4% to 1.4% of manganese, from 28% to 31.5% of chromium, from 8% to 12% of iron, from 2% to 7% of molybdenum, from 0.05% to 0.75% of aluminium, from 0.1% to 0.8% of titanium, from 0.6% to 2% in total of niobium and tantalum, the ratio of percentages of niobium plus tantalum and of silicon being at least 4, less than 0.04% of nitrogen, from 0.0008% to 0.0120% of zirconium, from 0.0010% to 0.0100% of boron, less than 0.01% of sulphur, less than 0.020% of phosphorus, less than 0.30% of copper, less than 0.15% of cobalt and less than 0.10% of tungsten, the remainder of the alloy, with the exception of unavoidable impurities of which the total content is at most 0.5%, consisting of nickel. The alloy is used, in particular, for the production of wires for the electro-gas welding of units or components of nuclear reactors and, more particularly, of pressurised water-cooled nuclear reactors.

Abstract: In order to prestress a tube (4) of a heat exchanger in tension in the axial direction, with precise tailoring of the prestress, at least one of the end parts (4a, 4b) of the tube (4) is expanded diametrally using a hydraulic pressure while the tube (4) is fixed at its ends in the tube plates (3a, 3b). The value of the prestress in each of the tubes (4) of the heat exchanger is tailored by altering the initial radial clearance between the external surface of the end part (4a, 4b) of the tube (4) and the internal surface of the hole (5) passing through the tube plate (3a, 3b) in which hole the end part (4a, 4b) of the tube (4) is engaged before diametrally expanding the end part. The end part (4a, 4b) of the tube which runs substantially over the entire length of the hole (5) passing through the tube plate (3a, 3b) is hydraulically diametrally expanded.