Abstract: Spent fuel rods are stored in a container. In order to improve the retention capacity of the barriers for radioactive emitters (radionuclides), the spent fuel rods are embedded in a bulk fill of zeolite and/or activated charcoal.

Abstract: Marking of the cuts which have to be made, cutting of the section at two ends, removal of the section which has to be replaced, bevelling of the joint ends of the parts remaining after the section has been cut out from the pipe, adjustment of a new or replacement section for length and bevelling of its joining ends and positioning and narrow bevel welding of the ends joining the replacement section to the ends of the remaining parts of the pipe are performed outside the pipe. Within the pipe operations of machining and inspecting an internal part of the joining ends welded together are performed by remote control in a programmed way by introducing and positioning means for working within the pipe from a component of the primary circuit.

Abstract: A safe start-up of a boiling water reactor is achieved when two conditions are adhered to and monitored when the control rods are being moved out of the core: First, the drive of a control rod should be activated only when the directly and diagonally adjacent control rods remain at rest simultaneously, and, second, when all the directly adjacent control rods are still in the fully moved-in initial position.

Abstract: In order, in a pressure accumulator, to generate a required operating pressure of a fluid situated in the pressure accumulator, a heater device is provided, disposed in an upper region of the pressure accumulator. The device generates a vapor cushion and the required operating pressure. Where necessary, when the fluid flows out, the pressure in the pressure accumulator is automatically reduced after the level has fallen below a defined filling level, as a result of the vapor condensing at a cold insulating device with a high heat-accumulation capacity. The pressure accumulator is preferably used as an emergency shut-down tank or as an emergency accumulator in a nuclear power plant.

Abstract: The present invention is drawn to an incremental link robot mast for vacuuming nuclear waste from a storage silo. The mast is made of incrementally linked segments that are clamshell in construction to enclose and shield the working cables of the vacuuming robot. Each segment is linked together as needed by a transverse hinge pin and two hydraulic connecting pins. The clamshell is hinged and latched together by an array of screws. The robot comprises a linked clamshell mast and a master-slave robot arm on the end of the mast which includes tools for viewing and breaking up the waste and vacuuming same to a removal area.

Abstract: A reactor pressure vessel with an upper support plate, in which an equalization opening is provided as a bypass is described. A process for temperature equalization between an upper dome chamber above a support plate and a lower chamber below it is described. It is proposed that the cross section of the equalization opening be variable as a function of the temperature, so that the flow of medium between the upper dome chamber and the lower chamber is varied as a function of the temperature.

Abstract: A method and apparatus for optimizing the production of Pu-238 in a nuclear reactor during normal reactor operation is disclosed wherein the production of Pu-238 is confined to one or more selectively replaced fuel cells with target cells located in the inside of the active volume of the reactor core to maximize the neutron flux for target irradiation. The target cells are modified existing nuclear fuel assembly cells having some fuel rods replaced with target rods of Np-237 forming a cluster array and having rings of water filled rods surrounding the target cluster to produce the desired optimal Pu-238 production.

Abstract: The present invention provides an improved abrasive delivery system for delivering an abrasive material to a waterjet cutting nozzle which has no external pressure effects on the orifice metering the flow of abrasive material from a container for the material by using air pressure to transport the abrasive material to the cutting nozzle through a standard metering orifice where equal pressure is maintained above and below the orifice to provide a constant volume of abrasive material flow to the cutting nozzle which is located up to 100 feet or more from the metering device.

Abstract: The maintenance device comprises a robot (2) for carrying out maintenance work in a remote-controlled or programmed way in the maintenance region. The robot (2) comprises a supporting part (2a) connected to a clamping support (3) secured to a means (4) of transporting the maintenance device (1) between an introductory region and the maintenance region. The clamping support (3) comprises clamping shoes (11, 13a, 13b) which can be moved in roughly parallel and opposite directions so as to clamp the maintenance device (1) in the maintenance region. The transport means (4) may be constructed in the form of a carriage comprising two motorized wheelsets. The device and the method of the invention make it possible in particular to carry out machining or inspection work inside primary pipes of a pressurized water nuclear reactor.

Abstract: An apparatus is described for catching and cooling a melt, in particular a core melt in a containment of a nuclear power plant. A porous body with which the melt comes into contact is provided. A pre-pressurized coolant is fed to the porous body so that the cavities in the porous body are filled with the coolant. After contact between the melt and the porous body, the pre-pressurized coolant penetrates into the melt and as a result leads to fragmentation, solidification and long-term cooling.

Abstract: For dosing lithium in cooling water containing cationic impurities or for reducing cationic impurities, the invention guides cooling water cycle through a first side of an electrodialysis unit and guides a concentration cycle through a second side of the electrodialysis unit. Cationic impurities are filtered out of the medium of the concentration cycle with a selective ion exchanger that is disposed in the concentration cycle.

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 pilot parts. The pilot parts are connected in series in the control line of the fitting and are each actuated by a pilot valve. The pilot parts open the fitting only when all the pilot parts are in a position which opens the fitting. The fitting closes as soon as even only one of the pilot parts is in a position which closes the fitting.

Abstract: The invention comprises an apparatus to repair a fuel assembly to accomplish a load lift comprising a main body, an upper section, a connection configured between the main body and the upper section and a lower section connected to the main body. The invention also comprises an inner adjusting body with a top and a bottom wherein a mandrel is connected to the bottom, the mandrel configured to actuate a holding body upon actuation of the inner adjusting body, the inner adjusting body positioned inside the upper section, the main body and the lower section and an actuator connected to the upper section, the actuator configured to actuate the inner adjusting body.

Abstract: An environmental monitoring system for a hazardous work area, such as a nuclear power plant, which monitors the radiation exposure of personnel working in the nuclear power plant and overlays a visual representation of the exposure data onto a video display of the location the personnel are working in. The apparatus includes a video source, such as a plurality of PTZ cameras, for providing video image signals of the work area. In the preferred embodiment, individual radiation exposure sensors provide signals representative of the radiation received by each worker in the work area. A computer, outside of the work area, is connected to the sensors for converting the sensor signals to a visual video representation of the sensor measurements. A gen/lock overlay unit is connected to the computer for combining the video image signals and the visual video representation of the sensor measurements wherein the visual video representations are overlaid onto the video images of the work area.

Abstract: A first antiradiation concrete includes a metallic aggregate having a grain size of up to 7 mm, and at least 5.0% by weight, in particular at least 7.8%, of a boron-containing aggregate having a grain size of up to 1 mm and being finer-grained than the metallic aggregate. A second antiradiation concrete includes a boron-containing aggregate having a grain size of up to 1 mm, and between 80 and 90% by weight, in particular 85 to 89%, of a metallic aggregate having a grain size of up to 7 mm. For the second concrete, the boron-containing aggregate is between 1.0 and 1.5% by weight. To achieve a shielding action that absorbs as much heat and radiation as possible, an antiradiation shell (2) has a wall region (2a to 2z) formed from the first or second antiradiation concrete where each has a boron-containing aggregate with a grain size up to 1 mm and a metallic aggregate grain size up to 7 mm.

Abstract: A furnace is provided for microwave sintering of nuclear fuel. A stationary wave is generated in an antenna cavity and used to extract microwaves through slots into a resonance chamber containing the nuclear fuel. A position of the slots is adjusted in such a way that a predetermined temperature profile is produced in the nuclear fuel.

Abstract: The radioactivity of a metal part is reduced in the process. In the method, firstly a layer of oxide is removed from the metal part using a decontamination solution. Then, an agent which has an oxidizing action and is still present is removed from the decontamination solution. As a result, a layer of the metal is removed. Since radionuclides are to be found only in the layer of the metal part which is close to the surface, the remaining metal can be scrapped in the conventional way.

Abstract: A device for sealing a tube in an opening which is located in a component. The tube is in particular a lance shaft and the component is in particular a nozzle connected to a cover of a reactor pressure vessel. A pressure element is in operative connection with the tube. As a result, the tube is pressed against the component. Provision is made for the pressure element to be driven hydraulically.

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: 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.