Abstract: A liquid metal cooled fast breeder nuclear reactor of the kind wherein the fuel assembly is submerged in a pool of liquid metal coolant in a primary vessel which is housed in a concrete vault. The fuel assembly, which comprises a multiplicity of elongate fuel pins, is sub-divided into a plurality of elongate sub-assembly constructions which upstand side-by-side. The fuel assembly has an inner zone comprised mainly of fissile material and a surrounding outer zone comprised mainly of breeder material. The sub-assemblies in the outer zone include electro-magnetic braking devices for regulating the flow of coolant through the sub-assemblies and the magnetic fields of the electro-magnetic braking devices are temperature sensitive being arranged so that as the power output of the breeder sub-assemblies increases the electro-magnetic resistance to coolant flow is reduced thereby maintaining the temperature of the coolant outlets from the sub-assemblies substantially constant.

Abstract: A method and apparatus for monitoring low concentrations of certain ions present in a flowing fluid is described in which an isokinetic sample is passed through an electro-separative cell wherein, under the influence of an applied electrical field microgram quantities of the ionic species are quantitatively transferred through a microporous filter membrane. The membrane has a pore size related to cell efficiency.

Abstract: Irradiated nuclear fuel is dissolved in nitric acid under a carbon dioxide atmosphere which is treated to remove iodine, krypton and xenon and recycled.

Abstract: In a fuel sub-assembly for a liquid metal cooled fast breeder nuclear reactor comprising a bundle of spaced fuel pins within a tubular wrapper having a spike extension for plugging into fuel assembly support structure the wrapper is pivotally connected to the spike extension.

Abstract: The reactor core is carried from the base region of the primary vessel by a strongback. An annular foot is attached to the inside surface of the leak jacket leaving a clearance of 6 mm between the foot and the outer surface of the base region of the primary vessel. In the event of deflection of the primary vessel, downward displacement of the core relative to the control rods is limited thereby avoiding serious reactivity instability.

Abstract: A tube-in-shell heat exchanger for effecting heat exchange between steam conducted by the heat exchange tubes and liquid metal conducted through the shell. The tubes penetrate the tube sheet by means of clearance apertures and are sealed thereto with thermal sleeves which are brazed to the tubes so that fusion welds are avoided in the sodium/water barrier.

Abstract: A coupling arrangement for coupling laddics in cascade comprises an emitter follower transistor circuit arranged so that the output impedance of the transistor restricts the rise and fall times in the mmf of the laddic output winding. The effect is to reduce the risk of spurious reset signals being generated in the output winding of sufficient amplitude to reset the next laddic in the cascade.

Abstract: In a chemical plant the atmosphere under which a chemical process is performed is contained and continuously circulated by the driving force obtained by the alternate condensation and evaporation of a part of the atmosphere.

Abstract: A process is disclosed for the separation of macromolecules from a fluid substance containing the macromolecules.The process comprises contacting the fluid substance with discrete porous particles having an interconnected porosity throughout which provides an extended surface area and a pore structure such as will allow the macromolecules to permeate the particles and be sorbed, the discrete porous particles being selected such that a proportion thereof have acidic surfaces for contacting the macromolecules in the fluid substance and a proportion thereof have basic surfaces for contacting the macromolecules in the fluid substance.A process for the separation of protein from milk whey solution is also disclosed.

Abstract: A liquid metal cooled fast breeder nuclear reactor has power setback means for use in an emergency. On initiation of a trip-signal a control rod is injected into the core in two stages, firstly, by free fall to effect an immediate power-set back to a safe level and, secondly, by controlled insertion. Total shut-down of the reactor under all emergencies is avoided.

Abstract: A colloidal dispersion is disclosed in which colloidal particles of an inorganic substance, and a compound of a Group IIA, or of a Group IIIA, or of a lanthanide (rare earth) element are dispersed throughout a liquid. The colloidal dispersion can be dried to form gels and the gels calcined to form porous ceramic materials.

Abstract: A fuel pin bracing grid for a nuclear fuel sub-assembly comprises a honeycomb array of unit cells formed from discrete strips. The cells are hexagonal, three alternate sides having windows and the remaining sides have linear groups of three embossments to provide guide pads for fuel pins. The openings provide a measure of compliancy for the grid to facilitate insertion and withdrawal of the pins. A fuel sub-assembly for a liquid metal cooled fast breeder nuclear reactor has a central fuel section with end extensions, the fuel section comprising a bundle of fuel pins in a hexagonal wrapper the pins being braced by a series of grids according to the invention. Reprocessing of the fuel is facilitated because the pins are withdrawable collectively from the compliant grids and wrapper combination merely by cutting an end extension from the wrapper.

Abstract: An interferometer which is compensated for the effects of low frequency vibrations in the measuring arm. The resultant changes in optical path length are detected and control signals are applied to an electro-optical device adapted to change the phase of the light in the reference arm of the interferometer relative to that in the measuring arm of the interferometer so as to compensate for the changes of optical path length in the measuring arm of the interferometer.

Abstract: In the manufacture of a superconducting member fine filaments of niobium or vanadium in a bronze matrix are formed by mechanical reduction, e.g. by drawing, and by solid state reaction the filaments are converted to superconducting filaments of a compound of niobium or vanadium with, typically, one or more of the elements aluminium, gallium, indium, silicon, germanium and tin included in the bronze. Phosphorus is included in the bronze but care is taken to ensure that the bronze in contact with the filaments is free of unwanted impurities and in particular has a very low concentration of phosphorus, desirably in the range 0.01 to 0.05 percent by weight.

Abstract: An electromagnetic pump wherein a core within a tubular housing defines an annular flow path for liquid metal, the core having helical windings of metal sheathed mineral insulated conductor and each winding comprising a plurality of loops arranged in series. The windings are in direct contact with the liquid metal and thereby reduce the magnetic gap normally required in such pumps.

Abstract: A temperature measuring device for measuring temperatures at axially spaced positions along the bore of a tube comprises a sensor in the form of a central rigid wire of constantan base alloy on to which thermocouple foils are spot welded at prescribed locations. The foils are silver plated over half their length thus forming a silver/constantan thermojunction; the constantan end of the junction only being welded to the rigid wire. A copper wire is crimped to the silver plated end of each foil. The detector may be supported coaxially within a resistance heated tube and in use the temperatures sensed by the thermocouples are continuously monitored.

Abstract: In a thermoelectric battery the heat source is suspended on the end of a thermoelectric unit, the other end of which is attached via a heat conducting mass to the casing. A resilient mounting permits resilient rocking of the thermoelectric unit to reduce stress on the unit in the event of shock or acceleration applied to the casing and spring fingers not normally in contact with the heat source or the thermoelectric unit are positioned to arrest the heat source if the assembly rocks more than a predetermined amount.

Abstract: A sealing member for insertion into a bore of a pipe comprising a flexible inflatable toroidal bag which when inflated expands radially outward to contact the bore of the pipe and expands radially inwards to obturate the pipe.

Abstract: An assembly for the transport and storage of nuclear fuel elements comprises a transport flask and a holder for fuel elements which fits within the flask. The assembly has self regulating ullage means which may comprise a plurality of eleongate reservoirs so designed that liquid is maintained in all the reservoirs when the assembly is in either the orientation used to load fuel elements into the assembly or in the orientation used to transport the fuel elements.

Abstract: An electrophoretic separation apparatus of the type described in U.S. Pat. No. 3,844,926 wherein the means for generating the electric field is constituted by an anode system and a cathode system, said systems being positioned on opposite sides of the annular separation chamber to one another and one or both of said systems comprising a semi-permeable membrane which defines the annular separation chamber, at least in part, and which is supported by a water-permeable resin-bonded cellulose fibre material, means for contacting said material with an electrolyte, and an electrode for supplying an electric current to the electrolyte.