Abstract: A nuclear fuel element for use in power-producing nuclear reactors, comprising a circular metal cladding tube containing sintered cylindrical oxide fuel pellets, the tube being formed internally with a substantially cylindrical inner surface having a plurality of longitudinal ribs forming axially extending channels. The fuel pellets have chamfered endfaces creating toroidal spaces at the adjoining ends of the fuel pellets, the ratio of axial channel to toroidal space volumes including any pellet dishing being at most about one (1);a process for the manufacture of such fuel element.

Abstract: A method of decontaminating radionuclide-contaminated acid insoluble corrosion products from primary system surfaces in pressurized water reactors by oxidation and concurrent dissolution in an acidic decontamination solution of the corrosion products which have been made acid-soluble by the oxidation. The characterizing feature of the method is that the oxidation is carried out at relatively low temperatures with a water-based oxidation agent having a pH below 7 and containing cerium nitrate, chromic acid and ozone.

Abstract: A completely cooled fast fluidized bed boiler comprises a reactor (4) having a bottom section (3), an integrated primary non-centrifugal mechanical particle separator (5), a gas pass (7) containing convective heat exchangers (10), and means (6,8,9) for controllably recirculating separated particles into the reactor bottom section (3). Reactor (4), separator (5) and gas pass (7) are built as an integrated unit within one and the same cooling system. The boiler is controlled by maintaining the bed temperature substantially constant or within a relatively narrow temperature interval by regulating the recirculation rate dependent on boiler load. For regulating the recirculation rate a non-mechanical valve, preferably a so-called L-valve (8), is used.

Abstract: A spent, radioactive, organic ion exchange resin is converted into a stable inorganic product having a considerably reduced volume in the following way. The radioactive ion exchange resin is mixed with a salt and an inorganic sorbent for radioactive nucleides, liberated by the salt, the mixture is dried and incinerated, whereupon the ash is solidified in cement.

Abstract: A completely cooled fast fluidized bed boiler comprises a reactor (4) having a bottom section (3), an integrated primary non-centrifugal mechanical particle separator (5), a gas pass (7) containing convective heat exchangers (10), and means (6,8,9) for controllably recirculating separated particles into the reactor bottom section (3). Reactor (4), separator (5) and gas pass (7) are built as an integrated unit within one and the same cooling system. The boiler is controlled by maintaining the bed temperature substantially constant or within a relatively narrow temperature interval by regulating the recirculation rate dependent on boiler load. For regulating the recirculation rate a non-mechanical valve, preferably a so-called L-valve (8), is used.

Abstract: Parameters of electrically conductive material at high temperature are measured by generating, by means of a transmitter coil, an electromagnetic alternating field which induces currents in the material and by detecting, by means of a receiver coil, a specific component of the secondary electromagnetic alternating field generated by the induced currents and dependent on the measured parameter, the frequency of the generated electromagnetic alternating field being such that the penetration depth of the field into the material is of the same geometrical order of magnitude as the characteristic geometrical dimension of the system, such as the distance between the receiver coil and the material. The specific component of the secondary electromagnetic alternating field is detected by means of a synchronous detector connected to the receiver coil and controlled by a phase-shifted signal from the transmitter.

Abstract: Radioactive waste, such as expended radioactive ion exchanger mass, can be transformed in a continuous process to a stable state for final storage in the following manner. The waste is mixed with an aqueous solution of a chemical agent which liberates radioactive substances from the waste, and with an inorganic sorbent for the thus liberated radioactive substances. The mixture is now dried and calcinated during the supply of air or oxygen so that the organic material is combusted. Subsequently the calcined material is placed in a refractory storage container, which is now heated with its contents to a temperature at which said material sinters or fuses to a stable product.

Abstract: When monitoring the period of a nuclear reactor, a signal representing the reactor power is generated and compared with a reference signal. When a difference between the power signal and the reference signal is detected, the level of the reference signal is changed at a predetermined rate independent of the magnitude of said difference in a direction to reduce said difference. Hereby the reference signal is brought to follow the power signal as long as the latter does not change faster than said predetermined rate of change for the reference signal. At least one warning level signal is generated, the level of which being equal to the instant level of the reference signal multiplied by a predetermined factor greater than one. The power signal is compared also with this warning level signal, and a warning signal is generated when the level of the power signal becomes equal to or exceeds the level of said warning level signal.

Abstract: A method at the transmission and reception of electromagnetically generated and received pulses of ultrasound, especially at non-destructive testing of electrically conductive material.The method comprises the steps of in a transmitter generating a first magnetic field by means of a first coil and a magnet core and supplying a transmitter coil located in the first magnetic field with a transmission pulse of ultrasonic frequency, and in a receiver generating a second magnetic field by means of a second coil and magnet core and by means of a receiver coil located in the second magnetic field receiving a signal originating from said transmitted pulse. When testing in this way nonmagnetic material, the signal/noise ratio is low. The noise partially originates from generated ultrasound affecting the transmitter and receiver magnets.

Abstract: A gas heating apparatus for divers comprises an electrical heating cartridge (1) which is replacably inserted with close fit into a gilled pipe (2) having an external helical flange (3). The pipe (2) is surrounded by a mantle (4) which is connected to a hood (8) with an outlet nozzle (9). The hood (8) and the pipe (2) is with a substantial play inserted into a pressure vessel (5,6,10). The vessel has an end cap (6) through which the hood nozzle (9) extends. The end cap (6) has also an inlet nozzle (7) for cold gas, which thus can flow through the gap (12) between the mantle (4) and the vessel wall (5) to the pipe end opposite the hood (8), and from there the gas flows in a helical path through a channel section defined by the flange (3) and the mantle (4) to the outlet nozzle (9) and is heated during passage along said path. The vessel also comprises an openable sealable compartment (19), wherein an electrical connection between the cartridge (1) and a power supply cable can be sealed from the ambient water.

Abstract: A lamp device for underwater use comprises a sealed beam lamp (1, 3, 5) mounted in a casing (7) designed as a pressure vessel, so that the lens part (1) of the sealed beam lamp constitutes part of the pressure vessel wall in the form of a pressure vessel lid and so that the back side (5) of the sealed beam lamp having the electrical connecting means of the sealed beam lamp is within a water-tight pressure chamber. The pressure vessel casing bears against the back side of the circumferential flange (3) of the sealed beam lamp, a ring sealing means (23) placed in a groove in the casing being arranged therebetween. The flange (3) is applied against the casing (7) by means of a ring plate (19) bearing against the front side of the flange via a pressure balancing packing (27), the ring plate being releasably tightened to the casing.

Abstract: A method and an apparatus for transmitting and receiving electromagnetic ultra-sound, especially in non-destructive testing of electrically conductive material, comprising the steps of generating one or more magnetic fields by means of one or more electromagnets (1,2,3,4) and supplying a transmitter coil (8) in said magnetic field with a supersonic frequency, and scanning a receiver coil (56) in said magnetic field. In known apparatuses, especially in the testing of non-magnetic material, the signal/noise ratio of a received signal is unfavorable.According to the present invention said ratio is improved in that said magnetic field is generated during a short time compared with the time between two successively occurring magnetic fields, and that a number of pulses of well-defined length of supersonic frequency are supplied to the transmitter coil (8) when the magnetic field or fields have a sufficient strength.

Abstract: A method and an apparatus for transmitting and receiving electromagnetically generated ultra-sound, particularly for non-destructive testing of electrically conductive material, comprising the steps of generating one or more magnetic fields by means of one or more electromagnets (1,2,3,4) and supplying to a transmitter coil (8) in said magnetic field a supersonic frequency, and scanning a receiver coil (52) in said magnetic field. For known apparatuses the signal/noise ratio of a received signal is unfavorable, especially at the testing of non-magnetic material.According to the present invention said ratio is improved in that said magnetic field is generated during a short time compared with the time between two subsequently occurring magnetic fields, and a pulse well-defined in length of supersonic frequency is supplied to the transmitter coil (8) about or at the maximum strength of the magnetic field or fields.

Abstract: A solar collector device is placed on a floating insulating lid of a rreservoir containing a heat storing liquid. The solar collector device comprises lens means which concentrate incident solar radiation to focal points or focal lines rear or at the lid, and the lid has apertures through which the focus portions of the radiation beams pass with snug clearance. Transparent evaporation preventing diaphragms seal the appertures. Electricity generating semi-transparent solar cells may be arranged in the apertures, whereby incident solar radiation partly produces electricity, partly heats the liquid, and whereby the liquid cools the cells. In the case the lens means comprise axially elongated lenses in parallel with the lid and the apertures are slots, aligned with the lens axes, the lid is rotatable whereby to maintain the lens axes, the slots and the sun radiation in one and the same plane during day time.

Abstract: A fish pond plant comprises a fish pond (1), a first conduit (2) for conducting sea water from the sea (11) to the fish pond (1), a second conduit (3) for conducting water from the pond to the sea, and pump means (4) for circulating sea water through the pond (1) via said conduits (2,3), a water magazine (5) associated with a solar collector (6) adapted to heat the magazine water, and a first heat exchanger (8) connected to said first and second conduits (2,3) to transfer heat from the sea water leaving the pond (1) to the fresh sea water entering the first conduit (2).A second heat exchanger (7) may be connected to the first conduit (2) and adapted to heat sea water fed to the first conduit (2) by heat exchange with warm magazine water.

Abstract: A method of reducing heat transmission through a window in a heated building, in a direction from the interior of the building to the building surroundings, while simultaneously maintaining complete visibility through the window both in, as well as against said direction, characterized in that a plastics film is applied to a window pane, said film being substantially fully transparent for visible light and which has substantially reduced transparency for a wavelength range corresponding to the heat radiation from the interior of the building. The film may comprise or consist of a polyethylene terephthalate film. Possibly a transparent polyvinyl fluoride film is also arranged in the window. Alternatively, a compound film comprising a polyethylene terephthalate film and a polyvinyl fluoride film is applied to the pane. Preferably the polyethylene terephthalate film is applied nearer to the interior of the building than the polyvinyl fluoride film.

Abstract: A heat pump contains a piston compressor which is driven by a piston engine. The refrigerant on the low pressure side of the heat pump drives the engine during the compression stroke of the engine. An accumulator chamber for the low pressure refrigerant is provided adjacent the compressor. The volume of the accumulator chamber is so large that the compressor piston, and consequently also the engine piston, is given a speed high enough for producing the required compression in the engine cylinder.