Abstract: An electrode (20) for electrochemical measurements in aqueous solutions at high temperatures, especially measurements in water in or from a primary or secondary circuit of a nuclear reactor in operation at a temperature of the water substantially prevailing at that time, comprises a conductor (21) of a platinum-group metal which for part of its extension is enclosed within a casing (22) making tight contact with the conductor and consisting of sintered-together particles of aluminum oxide, zirconium oxide or other electrically-insulating material which is inert to water. The conductor has one part (21a) exposed the aqueous solution and one connection part (21b) for connection to an electrical measuring member.

Abstract: A fuel assembly for a boiling water reactor comprises four bundles of vertical fuel rods (5). The bundles are surrounded by a common fuel channel (2) and each provided with a top tie plate (10) and a bottom tie plate (11). The four bottom tie plates are supported by a common supporting plate (18) which is inserted into, and supported by, the inlet sleeve (15) of the fuel assembly. Each bottom tie plate (11) includes an annular horizontal contact surface (24) abutting the supporting plate, and a non-round guide portion which is arranged, with no mentionable play, in a corresponding, non-round, through-hole (19) in the supporting plate (18).

Abstract: A fuel rod for a nuclear reactor comprises a cladding tube of a zirconium-based alloy, on the internal surface of which there is arranged a layer of zirconium containing 0.1-1 per cent by weight tin. The fuel rod contains a nuclear fuel preferably of uranium dioxide.

Abstract: A pressure-reducing valve for a dust-entraining gaseous or liquid fluent flow comprises a vertical tube containing a bed of particles which are fluidized by the flow. The particles have considerably greater specific weight than the dust in the flow, so that the particles in the bed are not carried away by the flow. The valve may be used to permit the continuous egress of a dust-contaminated flow from a pressurized container, for example a cyclone, while maintaining the pressure in the container. If the fluent flow is hot, the valve tube may be surrounded by a cooling jacket for extracting heat therefrom. The height of the bed in the tube may be adjusted to and from a particle storage, at the lower and upper ends, respectively, of the tube.

Abstract: A fuel asembly with a fuel channel (2) which surrounds a plurality of fuel rods (1) and which is divided, by means of a stiffening device (3) of cruciform cross-section and four wings (5), into four sub-channels (4) each of which comprises a bundle of fuel rods.Each fuel channel side has a plurality of stamped, inwardly-directed projections (6) arranged vertically one after the other, said projections being welded to one and the same stiffening wing. Each one of the wall portions located between the projections (6) defines, together with two adjacently positioned projections and a portion of the stiffening wing, a communication opening between two bundles located on one side each of the stiffening wing.

Abstract: A fuel assembly comprises a plurality of fuel rods arranged in a lattice with a combined quadratic and hexagonal geometry, about one-fourth of the total number of fuel rods in the fuel assembly constituting a group of rods at seventeen fuel rod positions among which nine positions are nodal points in a quadratic lattice portion located in the middle of the group.

Abstract: A flexible control rod for a nuclear reactor is built up of first, second, third and fourth absorber wings which are arranged in a cruciform configuration. Each wing is divided into a number of wing elements by slots extending substantially perpendicularly to the crossing line of the wings. The first and the third wings are arranged in a first plane with the slots in these wings located pairwise in line with each other, and the second and fourth wings are arranged in a second plane and also with their associated slots located pairwise in line. Further, the slots in the first plane are diplaced in parallel in the direction of the crossing line relative to the slots in the second plane, and the portions of the wing elements adjoining the crossing line of the wings are provided with recesses. This arrangement gives good flexibility without undue loss of strength.

Abstract: A fuel assembly is disclosed which comprises a fuel channel (1) with square cross-section supported by an inlet sleeve (22) having at its lower part an inlet opening for a flow of coolant flowing through the fuel assembly. The inlet sleeve (22) is made of stainless steel and is mechanically connected to a transition sleeve (21) made of thick zirconium alloy sheet, which is welded to the more thin-walled fuel channel (1).

Abstract: A method of treating a sheathing tube or fuel channel of a spent fuel box of a fuel assembly of a nuclear reactor comprises containing and reducing the volume of the sheathing tube prior to its disposal. The sheathing tube, after separation from a bottom piece of the fuel box, is placed in a protective tube. The protective tube and sheathing tube contained therein are then flattened and shaped into a convoluted form. Typically the flattening and shaping are performed in a single operation in a rolling mill, the protective tube and sheathing tube being rolled into a coil.

Abstract: A metallic, annular sealing device for closing an annular passage between a high-pressure chamber (2) and a circular cover (3) therefor. The sealing device comprises two coaxial, solid rings (17, 18) which are arranged with an intermediate circular gap. An upper (22) and a lower (21) hollow metal ring are each made with a circular gap. The edges of the gap of the upper hollow ring are welded to the solid rings (17, 18) at the upper portion of the gap defined between the solid rings, whereas the edges of the gap of the lower hollow ring are welded to the lower portion of the gap defined between the solid rings. Thus, the hollow rings (21, 22) communicate with each other.

Abstract: During combustion of a water-vapor generating sulfur-containing fuel, the pressurized flue gases are cooled, while extracting the main part of the latent heat of evaporation of the water vapor included and while removing sulfur impurities, using a coolant liquid in drop form in a scrubber. After having passed through the scrubber, the flue gases are mixed with a proportion of heated flue gases, which have previously passed through the scrubber, so that the temperature of the flue gases after said mixing exceeds the dew point for sulfuric acid in the flue gases. The flue gases are then heated in a heat exchanger and are thereafter expanded in an expansion machine to atmospheric pressure while reducing their temperature again without falling below the dew point for sulfuric acid.

Abstract: A concrete pressure vessel (1) for a nuclear reactor is formed with an arch (6) arranged above the cover (4) of the pressure vessel, said arch having a horizontally directed opening permitting horizontal transport of the cover. The cover (4) is retained by a plurality of compressive force transmitting elements (11) arranged between the cover and the arch (6).

Abstract: Fuel assembly having square cross-section and a plurality of tube elements (7,8) arranged in a square reactor lattice, at least one of said tube elements being water tubes (8) and a predominant number being fuel rods (7). Each fuel channel wall has a hollow projection (9) lying in a vertical mid-plane. The number of tube elements between two projections (9) lying in the same mid-plane is smaller than nine and greater than two. A plurality of rows of nine tube elements (7, 8) are arranged in parallel with each of the mid-planes.

Abstract: A pressurized water nuclear reactor comprises a reactor vessel arranged in a pool made in the form of a pressure vessel, the pool being filled with a strongly neutron-absorbing liquid, for example borated water. The reactor vessel, in addition to being connected to a primary system, is provided with a lower shutdown opening, arranged below the reactor core, for pool liquid and with an upper shutdown opening, arranged above the core, for pool liquid.

Abstract: A fuel assembly for a boiling water reactor comprises a plurality of fuel rods (2, 2'), which constitute four partial bundles and are surrounded by a fuel channel system (1) comprising one partial tube for each partial bundle. Each of the four partial bundles rests on a bottom tie plate (19) and is positioned with respect to the others by means of a common top tie plate (31), which is provided with a lifting loop (33) which is sufficiently strong to be able to lift the four partial bundles simultaneously, a major part of the lifting force being transmitted to said bottom tie plates via a plurality of supporting fuel rods (2').

Abstract: A fuel assembly for a boiling water reactor is provided with at least one vertical water channel (4, 5) for a by-pass flow through the fuel assembly. At its lower end the channel is connected to a radial tube (10) which opens out at the outer side surface of the fuel assembly. Below the radial tube, the wall of the assembly base (2) is provided with a through-hole (12).

Abstract: A boiling water reactor fuel assembly is provided with an elongated, vertical stiffening device having four stiffening wings (4) which are each attached to a wall of the fuel box. Each stiffening wing has at least one vertically directed passageway for water. The stiffening device has a cruciform cross-section and is composed of four elongated members (6, 6', 6", 6'") of L-shaped cross-sections.

Abstract: A pump for pumping a mixture of a liquid and a coarse-grained material comprises a motor-driven rotor (1) having a plurality of longitudinal cylinders (5, 6, 7, 8) having individual piston members (9), whereby these are driven back and forth by means of a pressure medium which is supplied to one end of the rotor. At the other end of the rotor, the cylinder openings, during rotation, pass a stationary inlet channel (21) and a stationary outlet channel (22) for the mass that is to be pumped. The rotor (1) is designed as a truncated cone, the cylinders being obliquely positioned with respect to the axis of rotation and having the greatest radial distance thereto at the cylinder ends which cooperate with the above-mentioned inlet and outlet channels.

Abstract: A fuel assembly for a boiling water reactor comprises a plurality of vertical fuel rods (1) and is furnished with a fuel channel device. The fuel rods are arranged with their lower ends resting on a bottom plate and positioned by means of a plurality of spacers (6) attached to the casing. The freedom of movement of the fuel rods in the upward direction is limited by means of a top plate (12) arranged above the upper end surfaces of the fuel rods (1).

Abstract: A nuclear reactor fuel assembly for a nuclear reactor comprises a housing with a wall and spacer means removably located within the housing, the spacer means comprising a plurality of spacer cells each adapted to receive an elongated fuel rod for the purpose of locating a bundle of such fuel rods in spaced-apart relationship within the housing. A portion of the housing which confronts the spacer means is provided at least at one location with a first locking means, and one of the spacer cells is provided with a second locking means movable between active and inactive positions. This second locking means is prevented from moving past the first locking means in the direction of elongation of the fuel rods when the second locking means is in its active position but is able to move past the first locking means when in its inactive position. The second locking means is moved from its inactive position to its active position by the insertion of a fuel rod into said one spacer cell.