Abstract: The operating temperature of a laser can be assessed by determining the ratio of light of different wavelengths emitted by the laser. A copper vapor laser emits green and yellow light having two distinct wavelengths and the ratio of said wavelengths is temperature dependant. Preferably the ratio of green to yellow light is in the region of 2 to 1 for optimum operating conditions. The ratio is determined using green and yellow light filters (3, 4) having associated light dependant resistors (6, 7) forming input and feedback resistors in an operational amplifier circuit (9).

Abstract: A container for nuclear fuel comprises a number of cells for receiving the nuclear fuel. The cells have removable lids and are disposed in a progressive manner in a parallel series relationship. A vent is provided between adjacent cells and an inlet for a pressurizing gas is located at the first cell. A valve at the last cell allows fluid to be discharged from that cell.

Abstract: A mixing method uses, and a colloidal grout mixing apparatus comprises, an upright cylindrical vessel in which a mixer is located. The mixer comprises a shaft extending substantially co-axially with the longitudinal axis of the vessel, and a paddle assembly mounted on the shaft. The paddle assembly produces a vortex in liquid in the vessel, and also provides a high shear region near the base of the vessel. A non-shear pump is connected to the base to discharge grout from the vessel. The grout may be discharged to a drum containing radioactive waste and mounted on a vibratory platform.

Abstract: A containment, such as a glovebox (3), includes an extract system comprising an extract suction means, a filter housing (4), and a vortex amplifier (1) controlling the extent of suction by the suction means from the containment, wherein the vortex amplifier is removably mounted in an opening in a wall (2) of the containment, and the filter housing is mounted relative to the containment in such a manner that a filter (22) within the housing can be posted through an opening into the containment.The vortex amplifier is removable for cleaning.The filter housing may be mounted on the exterior of the containment in-line with the opening in which the vortex amplifier is mounted whereby the filter can be posted through the opening in which the vortex amplifier is mounted upon removal of the vortex amplifier.

Abstract: Apparatus for locating a floatable platform, comprises upstanding support members arranged to be adjacent to an article submerged in a liquid, and extendible members depending from the platform. The extendible members on initial extension are arranged to locate on the support members, and further extension of the extendible members raises the platform from a buoyant to a partially-buoyant state. A laser device on the platform is arranged to scan a stationary coded target so as to determine the position of the platform.

Abstract: A method of welding in which an inert gaseous shield at a welding zone is provided by a mixture of gases of different densities. The proportions of the individual gases in the mixture are controlled to ensure that the density of the gas mixture is about the same as the density of the surrounding atmospheric air. Cryogenic means may be used to form a condensed gas plug in a pipe or the like to be welded.

Abstract: A method of manufacturing sintered uranium dioxide in which a mixture is formed of single crystals of uranium dioxide and uranium dioxide powder. Compacts are formed from granules of the mixture, the compacts are sintered in carbon dioxide, and then reduced in a hydrogen environment at a substantially lower temperature than the sintering temperature. The quantity of the single crystals is selected so as to inhibit excessive grain growth in the compacts during sintering.

Abstract: A process for the treatment of a material which is or is suspected to contain or carry one or more actinides or compounds thereof to dissolve such actinides or compounds comprises contacting the material with an aqueous solution having a pH in the range 5.5 to 10.5 which is free of heavy metal ions and comprises ingredients which are naturally degradable to non-toxic products with or without mild physical assistance such as heat or ultra-violet radiation, said solution comprising:(a) carbonated water;(b) a conditioning agent;and (c) a complexing agent which comprises the anion of a carboxylic acid having from 2 to 6 carbon atoms.The process may be employed to separate spent nuclear fuel from its metal containment or it may be employed to decontaminate surface, e.g. concrete or soil or pipes carrying traces of actinides, or bulk materials such as soil or rubble.

Abstract: A process for cleaning solutions of an alkylphosphate in a hydrophobic organic solvent. The process involves the steps of washing the solution with aqueous sulphuric acid, and contacting the washed solution with an ion exchange material. The ion exchange material may be a resin of the type designated as styrene divinyl benzene copolymers.

Abstract: A container for material contaminated with a toxic substance or a radionuclide has a base with recesses. A highly absorbent cementitious material is disposed in the recesses for absorbing any liquid in the container. The cementitious material is made by mixing together a sodium bentonite clay slurry and a cement slurry at a water/solids ratio of about 1.5/1. Subsequent heating of the mixture removes capillary water without substantially dehydrating any hydrated cement.

Abstract: Particulates from a source fall into a tundish which discharges to a collection chamber. The build-up of particulates in the chamber is sensed, and a valve opened at the bottom of the chamber when a pre-determined level of the particulates is sensed in the chamber. A valve at the top of the chamber may be closed at the same time so that pressurized air can be injected into the chamber to expel the particulates through the bottom of the chamber through the valve. A filter circuit may be connected to the tundish to assist in removing particulates from the tundish.

Abstract: A non-consumable electrode for tungsten inert gas welding. The electrode is formed from at least two portions in face-to-face relationship so as to define a longitudinal slit between them extending lengthwise of the electrode and terminating at the tip of the electrode. The slit acts as a cavity and ensures that spark initiation takes place from locations on the electrode where metal ion deposition is inhibited. The faces of the portions may be of flat form or of complementary contoured form.

Abstract: Wastes are placed in a container, and the container is closed by a lid having a port sealed by a disc. A cutting tool having a hollow drive stem pierces the disc. A grout slurry is fed through the stem so as to discharge into the container and embed the wastes in the grout when set. The wastes may be contained in a crate in the container, and may also take the form of a glove box which itself contains waste objects.

Abstract: In a copper vapor laser, individual copper loads are each placed in a respective ceramic crucible and the crucibles are spaced apart at intervals along the length of the laser discharge tube.

Abstract: A filter module (11) comprises a housing divided internally by a partition (14) into two compartments (15, 16). At least one hollow cylindrical filter element (12) is housed in one of the compartments, the or each filter element fitting about an opening (19) in the partition (14). A filter assembly (10) comprises a plurality of filter modules (11) mounted in a fluid flow line (13) such that incoming fluid enters one of the compartments, flows through the walls of the filter elements and filtered flow emerges from the other compartment.

Abstract: The invention concerns a filter system having a plurality of individual removable filter units disposed between inlet and outlet ducts for a gas flow path to filter the gas flow. The system comprises one or more filter ports between the inlet duct (3,5) and the outlet duct (4,6) to receive removable filter units (1), a transfer port (25) co-operable with and sealable by a flask (20) for the filter units, a seal plate (14) removably located in the transfer port, means (15) for removing the seal plate, a carriage (18) movable between the transfer port and the filter port or ports, means (15) for placing filter units on or removing filter units from the carriage adjacent to the transfer port and means (8) for placing filter units on or removing filter units from the carriage adjacent to the filter port or ports. The system may be used to filter from a gas flow harmful or potentially harmful substances, e.g. particles which are radioactive, toxic or biologically active.

Abstract: Alkyl phosphates, which may be dissolved in a hydrocarbon solvent can be destroyed in a two-stage process, the first stage involving hydrolysis with concentrated alkali to effect partial de-alkylation of the alkyl phosphate the second stage involving catalytic oxidation of the de-alkylated phosphate with hydrogen peroxide. This results in improved safety as oxidation takes place after much of the hydrocarbon has been removed at the first stage.

Abstract: A transfer apparatus having a platform in the form of two members extending in adjacent parallel relationship in a substantially linear direction. Vibrators are arranged to oscillate the members independently of each other in out-of-phase relationship in the linear direction. The members may have their faces in angular facing relationship. The faces of the members have thereon cushion elements which comprise a multiplicity of extremely fine, flexible synthetic polymer fibers having a length no greater than about 2.5mm, and an inclined orientation of at least 70.degree. from a backing.

Abstract: A rotary contactor (10) suitable for liquid/liquid extraction processes in a nuclear fuel reprocessing plant includes a rotor (14) with a contacting chamber (16) defined within it, the chamber being of annular shape with its radial width considerably less than its inner radius. Neutron absorbing material (22) inhibits neutron transmission between different parts of the contactor. Where the rotation axis is upright, liquids may be fed into the contactor via open-topped annular feed channels (30, 32) at the upper surface of the rotor (14). The chamber (16) includes a packing material (42) such as wire mesh, random or structured packing. The contactor also includes an arrangement to control the radial position of the liquid/liquid coalescing interface, or to control the radial position at which one of the liquids is taken off, which may be operated by gas pressure.

Abstract: Circuit breakers can be used to replace fuses in plant comprising centrifuge machines driven by small three-phase electric motors. The circuit breakers incorporate three bi-metal strips which bend due to the heat produced by current flow. Loss of current in one phase results in unequal bending of these trips. In one arrangement, a light-emitting diode 5 fitted to a first strip 2 produced light to pass through an aperture 8 in a plate 7 on the second strip 3 to fall on a photo-sensitive detector 6 on the third strip 4. Any unequal bending causes the light to be cut-off and the resulting signal can be used to trip the circuit breaker. In some cases the strips are the strips in the circuit breaker.