Abstract: A rotary kiln assembly comprising an inlet arrangement, a rotary kiln and an outlet arrangement. A seal arrangement is provided between the inlet arrangement and the rotary kiln and a seal arrangement is provided between the rotary kiln and the outlet arrangement. It is a problem with rotary kiln assemblies to remove the seals without relative movement of the rotary kiln or the inlet or outlet arrangements. At least one of the seal arrangements is made retractable in telescopic manner and the kiln assembly includes detachable spacing means such that the retractable seal arrangement can be removed from the kiln assembly as a unit without fouling or movement of the kiln or the inlet or outlet arrangements and hence without disturbing their alignment. The spacer means may be detachable only after retraction of the sealing arrangement and may be integral with a part of the sealing arrangement.

Abstract: The lower end of an ion exchange column is provided with a rotatable valve member which, in a first position, supports resin material in the column and, in a second position, allows the resin material to drop out of the column. The valve member can include a sintered body which in the first position supports the resin material and permits drainage of reagents introduced into the column. On rotating the valve member into its second position the sintered body can fall out of the valve member to permit the resin material to fall out of the column through the valve member. A replacement sintered body can be dropped down the column on to the valve member and the column can be refilled with resin material for further use.

Abstract: A problem that can occur with a large rotary kiln assembly is that it can move out of position or seals can become defective, making an escape of materials possible. The present invention provides transducers (10, 15) for detecting movement of the rotary kiln itself or part of a seal assembly secured thereto relative to an inlet/outlet arrangement of the kiln assembly or a part of a seal arrangement secured thereto and also means whereby the condition of the seals can be monitored by following changes in the pressure or flow rate of a purge gas. If the rotary kiln (2) should move out of alignment, then corrective action can be taken. If the seals should leak, then they are changed. A record of kiln movement is provided and if movement is excessive, an alarm (20) is sounded.

Abstract: A flask for the transport and storage of irradiated nuclear fuel comprises a hollow cylindrical container having cooling fins surrounded by a jacket of neutron shielding material. The jacket can be formed in two semi-cylindrical portions which are hinged together and held tight about the container. The jacket is spaced radially from the extremities of the cooling fins.

Abstract: A sampling system in which carriers (1) containing sample bottles (4) are transported by pneumatic conveyor means (3) between an examination station, for example a laboratory, and a selected sampling station at a plant. On arrival at a sampling station (2) a bottle (4) is moved through a predetermined sequence of movements by a transfer arm (5) to cause the bottle to be removed from its carrier and placed over a sample dispenser (7) to introduce sample into the bottle. The bottle containing sample is then returned to the carrier for return to the examination station.

Abstract: In a gas centrifuge assembly comprising a cascade of individual gas centrifuge machines, malfunctioning of any one of the machines as a result of the presence of gaseous impurity within that machine is inhibited from spreading to other machines in the cascade by flow operated valve arrangements in gas flow lines associated with each machine in the cascade. Each valve arrangement is constructed and arranged to close in response to an abnormal gas flow in the line and out of the machine arising from gaseous impurity within the machine. The valve arrangements may be located in some or all of the feed, product and tails lines of each centrifuge machine in the cascade.

Abstract: A gate assembly for sub-dividing a pond or reservoir into separate compartments comprises a gate (1) vertically slidable in a cooperating frame (2) secured in the floor and side walls of the pond. The frame (2) is of channel section and a sealing member (9) on the gate (1) cooperates with the frame (1) to provide a seal therebetween. The gate (1) is drawn against the frame (2) as it is lowered into position by means of cooperating wedge members (16,17) on the frame and the gate. On draining the compartment (4) at the side of the gate (1) carrying the sealing member (9) the gate is further urged into sealing engagement with the frame (2) by the pressure of the liquid in the compartment (3) at the opposite side of the gate (1).

Abstract: The invention provides ultrasonic apparatus 64 for measuring the amplitude of oscillation of a fluid. The apparatus 64 combines an ultrasonic flowmeter 60, 62, 65 which gives an indication of velocity of the fluid, with an integrating circuit 74. The integration is carried out over successive half-cycles of the oscillation, and may be arranged to give an average value of the amplitude.

Abstract: The slave arm (15) in a sealed containment (12 or 210) is arranged to be replaceable by forward displacement by a new arm (115 or 215). The new arm is preceded by an intermediate sealing body (101 or 201) sealed on the new arm by a flexible bag (103 or 203) which is removable into the sealed containment once the new arm is located in the sealed containment. Preferably the sealed containment (12) is spaced from a shield wall (10) to provide an interspace (13) accessible to a protected operator and the linking part (16) of the manipulator has a demountable coupling (24) in the interspace so that the new arm can be inserted from the interspace.

Abstract: A welding electrode comprises an elongate body with a cavity or cavities at one end thereof. The geometry of the cavity or cavities can range from a single simple slot arranged to extend along a diameter of the electrode tip and in the axial direction to terminate short of the region where the taper of the electrode tip commences, to complex cavities such as multi slots. Electrodes according to the invention serve to mitigate the problem of their becoming coated with metal vaporized from the surface of the weld pool.

Abstract: A pond for the storage of hazardous materials, such as irradiated nuclear fuel elements, under water. Upper (8) and lower (6) impervious membranes extend without interruption beneath the floor (1) of the pond and the edges of the membranes lead into a trench (9) surrounding the pond. Any leakage through the floor is directed normally by the upper membrane (8) into the trench (9). The lower membrane (6) provides an additional impervious barrier in the event of a leak in the upper membrane (8) and again directs the leakage into the trench thereby avoiding contamination of the ground beneath the pond.

Abstract: A method and apparatus for charging radioactive waste into a disposable steel drum having a plug type lid. The drum is sealed to a waste dispenser and the dispenser closure and lid are withdrawn into the dispenser in back-to-back manner. Before reclosing the dispenser the drum is urged closer to it so that on restoring the dispenser closure to the closed position the lid is pressed into the drum opening.

Abstract: An aluminium valve which has a seat of stainless steel. This seat is provided by friction welding stainless steel onto aluminium and then shaping the composite to size. The stainless steel can be covered with stellite. The valve is closed by abutment of a PTFE bush onto the seats. The seat can comprise a slope so that any contaminatory material tends to be forced off the seat by the bush in use.

Abstract: An hydraulic system for the discharge of a bed of granular material supported on a screen (3), for example a sand filter, comprises an upright cylindrical vessel (1) with a horizontal plate (2) at the lower end of the vessel to support the bed of granular material. The support plate carries screens (3) to allow the passage of water and to block the passage of bed material. The vessel is provided with entry and discharge ports (8 and 10) and a ring of fluidizing jets (13) is located a short distance above the support plate (2). A discharge pipe (11) rises through the bed. The bed of material can be discharged hydraulically from the vessel through the discharge pipe (11) without any mechanical items requiring maintenance within the vessel (1).

Abstract: An apparatus for agitating and transforming settled sludges into slurries which are then capable of being pumped by conventional means. The apparatus comprises a housing immersible in the contents of a tank or chamber and containing separate variable drive means for an impeller and an impeller casing. The impeller casing forms an inlet to the impeller and has a plurality of radially directed outlet nozzles whereby rotation of the impeller effects circulation of the contents of the tank or chamber from the inlet to the outlets and rotation of the casing causes the discharge at the outlets to agitate the contents. The discharge at the outlets breaks up solid sediment at the bottom of the tank or chamber and a continuous recirculation of the contents results in the formation of a slurry.

Abstract: A boiler for vaporizing liquid hydrogen fluoride has a heat transfer surface arranged to be covered increasingly by the liquid as the liquid level rises so that the heat supplied to the boiler can be adjusted to maintain a constant level of liquid in the boiler and thereby equate the feed rate of liquid hydrogen fluoride to that vaporized. Thus by metering and controlling the feed rate of the liquid the feed rate of the vapor can be metered and controlled.

Abstract: A pelleting press in which the die has at least a part which is fluid-permeable so that powder in the die can be compressed simultaneously by fluid permeating the die and mechanically from at least one end of the die. It has a particular application in the pelleting of nuclear fuel powders.The die may be of reaction - sintered silicon carbide rendered fluid-permeable by removal of silicon.

Abstract: A method and apparatus for separating particles suspended in a liquid from the liquid. A flow of the liquid is passed through a filter bed of ferromagnetic bodies which acts as a coarse filter to trap the larger particles in the flow. The filter bed is arranged within a truncated cone between the poles of an electromagnet. To cleanse the bed and flush out the trapped particles a wash liquid is passed through the bed and the electromagnet is energized to levitate the bed to thereby allow the wash liquid to remove the particles. The liquid flow from the coarse filter can be passed to a high gradient magnetic separator at which remaining small particles in the flow are filtered magnetically.

Abstract: A spacer grid for fuel assemblies in a water reactor is provided. The grid shell is shaped so that a pressing in Zircaloy can be made. Cross members in a lattice in the shell provide spacing for the fuel pins of the fuel assembly. Each fuel pin has its own cell in the lattice, and at least some of the joints between the members comprise two attachment points spaced along one of the members at a single intersection.

Abstract: A bellows-type valve includes several additional safeguards in the form of back-up seals which are effective to prevent in- or out-leakage should the bellows fail. Some of the seals can be changed while the valve remains closed. There is provision for testing the integrity of the seals while the valve remains operative.