Abstract: A magnetic filter in which an elongate ferromagnetic filter member is disposed within a housing having an inlet for fluid to be filtered and an outlet for filtrate with magnet means outside the housing for creating a magnetic field across the filter member. The member conveniently is in the form of an array of spaced apart bars of rectangular cross-section, the magnetic field being directed normal to the longitudinal axes of the bars and substantially parallel to the longer cross-sectional side of each bar.

Abstract: A reaction-sintered silicon carbide body having portions differing from each other in free silicon content and such a body with a surface layer rendered more readily abradable than the remainder of the body by the removal of free silicon from the surface layer. It has a particular application in the provision of shrouds for gas turbines, which can be produced by slip-casting in two stages.

Abstract: Radioactive liquids are stored in coils placed in tanks containing circulating cooling medium. The liquid in the coil is circulated by a fluidic pump. In the event of a failure in the pumps circulating the cooling medium the decay heat will cause the cooling medium to boil. A reflux condensor fitted to the tank prevents loss of cooling medium during such periods of pump malfunction.

Abstract: A reaction bonded silicon carbide body in which there is included in the free silicon phase of the body to modify the electrical resistivity of the body, at least one of the Group III elements boron and indium or at least one of the Group V elements antimony and tantalum. The element may be added in compound form and may be included in the green body prior to reaction bonding or in the silicon with which it is reaction bonded.

Abstract: In a process for reducing the oxygen content of metal oxide material, particularly a nuclear fuel material, the metal oxide material is contained in a plurality of carbon crucibles which are moved through a heated zone in end-to-end contact counter current to a stream of hydrogen-containing gas.

Abstract: The invention is concerned with providing substrates with coatings obtainable from sols, for example to protect the substrate (such as in nuclear reactors or hydrocarbon cracking plant) or to provide a carrier for catalytically active material.Hitherto, coatings obtained from sols have had a high porosity and high surface area so that they have not been entirely satisfactory for the above applications.In the invention, dense, low-porosity coatings are provided by contacting the substrate with a sol of refractory material (e.g. CeO.sub.2 or SiO.sub.2) convertible to a gel of density at least 40% of the theoretical density of the refractory material, and converting the sol to the gel. Optionally, the gel may be converted to a ceramic coating by firing.

Abstract: Heat exchange apparatus for use in a liquid metal environment comprising heat exchange tubes and grid plates having complementary bearing surfaces. The tubes are of stainless steel and the complementary bearing surfaces of the grids are aluminized to reduce wear and friction.

Abstract: A method of leaching a material from a cavity having a closed or a partially closed top. The method consists of subjecting the liquid to a number of pressure cycles, each pressure cycle involving a decrease in pressure to cause boiling of the liquid, followed by a rise in pressure to inhibit the boiling. The method may include the step of heating the liquid to a temperature near to its boiling point.

Abstract: A liquid metal cooled fast breeder nuclear reactor of the pool kind has an intermediate heat exchange module comprising a tube-in-shell heat exchanger and an electromagnetic flow coupler in the base region of the module. Primary coolant is flowed through the heat exchanger being driven by electromagnetic interaction with secondary liquid metal coolant flow effected by a mechanical pump.

Abstract: There is disclosed a method for the preparation of a shaped body which includes the step of cold pressing a material to give the shaped body, wherein the material has been prepared by means of a gelation process and not substantially comminuted prior to cold pressing.The shaped body can be heated subsequently to pressing to produce a sintered shaped body.Preferably the material for pressing, prepared by a gelation process and not substantially comminuted, is a selected physical configuration.

Abstract: A nuclear fuel pin for a fast breeder nuclear reactor has a central fissile region containing fissile material in the form of vibro-compacted microspheres and axial breeder regions above and below the central region containing fertile material in the form of pellets or packed microspheres. The microspheres containing fissile material are of two sizes with the smaller microspheres packed into the interstices between the larger microspheres. To prevent intermixing of the material of the fissile and fertile regions a barrier layer is located between the fissile region and each breeder region which comprises a layer of microspheres having a diameter intermediate the diameter of the larger and smaller diameter microspheres of the fissile region.

Abstract: An interconnection between screened cables and a method of interconnecting screened cables. It is calculated that reduction of magnetic reluctance of the magnetic path between inner and outer surfaces of the screen in the region of the interconnection decreases external interference to the screened cable and the interconnections are constructed to be in accordance with this calculation. Mu-metal can be used to reduce magnetic reluctance.

Abstract: The invention relates to the coating of particles for use, for example, as inoculants in the metallurgical field.A fluidized bed of metallic-particles (e.g. Fe/Si, Fe/Mn of size range 50 .mu.m to 3000 .mu.m or higher) is contacted with a wash-coat comprising a suspension of a non-dispersible ceramic powder in a sol (e.g. a suspension of Al(OH).sub.3 powder in a boehmite sol). Subsequent controlled drying and firing produces a ceramic coating on the particles which has good adhesion and thermal stability and whose thickness and density can readily be controlled.

Abstract: A process for manufacturing gallium arsenide devices in which regions of high resistivity are created in the gallium arsenide by subjecting the regions to bombardment by protons and then by deuterons, and devices so made.

Abstract: A process for treating a titanium containing artefact to inhibit fretting corrosion, in which an active species having a higher heat of formation of its oxide than titanium is deposited on the artefact in vacuo, and the artefact is then heated sufficiently to cause the active species to migrate into the artefact to provide a surface region thereof containing the active species. Preferably the active species is deposited by an ion bombardment technique.

Abstract: A device for the treatment of fluids in which the fluid is caused to contact the device. The device is particularly useful in the field of catalysis. The device comprises a plurality of substantially parallel elongate helically wound coils of wire connected together by a connecting member to form a sheet of interconnected coils. In the case where the device is used for the treatment of the fluid by catalysis, the wire is made from, or coated with, a catalytically active material.

Abstract: A transverse flow gas discharge laser in which the cathode has an elongated cross-section the larger dimension of which is positioned at an angle to the direction of flow of the gaseous lasing medium. The anode of the laser is of modular construction and consists of an array of individually ballasted cylindrical buttons. Both the anode and the cathode are so positioned that they intereact aerodynamically with the adjacent duct wall to produce a stable electric discharge between them.

Abstract: There is disclosed a method for the preparation of a shaped body which includes pressing a powder to give a "green" shaped body wherein the powder has been made by comminuting a material prepared by means of a gelation process, the material prior to comminuting being of a selected physical configuration.The invention finds application in relation to the handling and transportation of nuclear fuels and nuclear fuel materials. Thus, a material prepared by means of gelation process can be transported and handled in an environmentally desirable, substantially dust-free form (e.g. spherical particles) and then comminuted to produce a powder for pressing into a shaped nuclear fuel body.

Abstract: The size and shape of a body is determined by rolling it between the plates of capacitors, the dielectric constant of which is thereby changed. A capacitor scans sections of the body along its longitudinal axis to detect its diameter and surface faults, a second determines the body's length and a third determines the position of the body. The changes in dielectric constant are compared with those produced by a body of known size and shape so that the size and shape of the body can be determined.

Abstract: Apparatus for the continuous forming of material by extrusion and having a rotatable wheel member with an endless groove therein, a stationary shoe member overlying part of the length of the groove and having a portion which projects into said part of the length of the groove and is of a width substantially equal to that of the groove so as to form a passageway therewith, a stationary abutment member associated with the shoe member and projecting into the groove so as to block the downstream end of the passageway, is characterized by the improvement that the wheel member has one or more endless grooves in its periphery, arranged in parallel planes where more than one groove is provided, the shoe member has as many projecting portions as grooves, the or each projecting portion engages the or the respective groove, a duct leads from the passageway formed by the shoe member with the or each groove, through the or the respective projecting portion into a single chamber formed in the shoe member, and one or more d