Abstract: An event monitoring system has a plurality of detector units for detecting neutrons or other emissions from radioactive materials (i.e., events). At least one of the detector units has a detector for the events and an amplifier to amplify signals generated by the detector. A signal handler receives the amplified signals and an adder adds to the signals an indication of the detector unit from which the signals originated. A combiner combines the signals. A serial link conveys the combined signals from the signal handler to a signal processor which includes a signal receiver for the combined signals. A time stamper applies to the signal an indication of time of the generation of the signal by the detector unit, and a computer processes the signals, including the time and detector unit indications, using software to produce information on the signals or events they represent.

Abstract: The invention is directed towards improved accuracy of investigations into corrosion using the methods and apparatus of the invention. In particular, the invention provides a method of investigating corrosion at a location, the method including measuring the variation in the voltage between two or more electrical contacts at a first time and at one or more other times, the two or more electrical contacts being in contact with the location, passing a current through the location at the time of the voltage measurements, providing a power source external of the location to provide an applied current, using the respective voltage values from the two or more electrical contacts in the investigation of the corrosion, the part of the applied current passing through the location being measured by the use of the Hall effect.

Abstract: An inductively coupled plasma source mass spectrometer is equipped with a multidimensional detector system wherein ions transmitted by the mass spectrometer are detected.

Abstract: A method of investigating corrosion includes providing a mounting unit for two or more electrical contacts, introducing the mounting unit to a replica of a location which has not corroded, measuring the voltage between the two or more electrical contacts at one or more times, the two or more electrical contacts being in contact with the replica of the location being investigated, introducing the mounting unit to the location which may have corroded, measuring the voltage between and/or the variation in the voltage between two or more electrical contacts at a first time and at one or more other times, the two or more electrical contacts being in contact with the location being investigated, passing a current through the replica location at the time of the voltage measurement and through the location at the time of the voltage measurements, the voltage measurements for the location indicating the extent of corrosion.

Abstract: A transport container for nuclear fuel is provided with an outer container having internal insulation, the insulation defining an internal cavity. The cavity receives a plurality of fuel containers wherein the internal volume of the fuel containers is at least 5% of the external volume of the outer container. The container allows substantially higher volume proportions of enriched fuel to be safely transported than is possible with prior containers.

Abstract: The invention provides apparatus and methods which facilitate movement of an instrument relative to an item or location being monitored and/or the item or location relative to the instrument, whilst successfully excluding extraneous ions from the detection location. Thus, ions generated by emissions from the item or location can successfully be monitored during movement. The technique employs sealing to exclude such ions, for instance, through an electro-field which attracts and discharges the ions prior to their entering the detecting location and/or using a magnetic field configured to repel the ions away from the detecting location.

Abstract: A method and apparatus are provided for determining radiation dose rates at selected locations within an environment. Incident gamma ray energy and count rate are measured at one or more measured locations within the environment to obtain a measured spectrum for those measured locations. The spatial position of the measured locations is also measured. An emitted spectrum is then determined for the measured locations based on the measured spectrum. The emitted spectrum may then be used to determine the dose rate at one or more selected locations (which may be different than the measured locations). In this way the invention provides an accurate solution for the dose rate at any point of interest within the environment based on the measured count and incident energies.

Abstract: A sealable container for receiving toxic waste for long-term storage is described, the container comprising sheet metal members welded together to form a main fillable volume; four hollow, sheet metal, vertically directed leg portions situated at corner positions on the container, and, a separate lid member fixable to the container to seal at least the main fillable volume wherein the majority of the weld length utilized in the container construction is constituted by fillet welds. Further constructions are described having means to prevent flotation of waste in a liquid grout prior to solidification thereof and constructions where the leg volumes are independently fillable of the main volume.

Abstract: The invention provides improved methods and apparatus for investigating emissions from radioactive sources within an environment. In particular, the method deploys a collimated detector to scan the environment and obtain approximate position information on sources within that environment together with further investigations using a moveable shielding component which is moved relative to the field of view of the collimator. In an alternative technique, the collimator is moved in two different directions to achieve positional information using scanning.

Abstract: A casing for the protection of an article contained within the casing is described, the protective casing comprising: at least two casing members which are assemblable to constitute a casing having an internal volume to receive the article, each of said at least two casing members comprising: an outer skin of fiber reinforced plastics material having a plurality of layers of reinforcing fibers in a plastics material matrix; an inner skin of fiber reinforced plastics material having a plurality of layers of reinforcing fibers in a plastics material matrix; a filling of a low density core material in a space between the outer and inner skin members; sealing means disposed in the joint face between said at least two casing members; and fastener means to hold said at least two members together.

Abstract: The invention provides a technique for correcting gamma ray intensities detected to account for variation in attenuation effects with energy. The corrected intensity values enable more accurate isotopic analysis to be conducted and render such techniques applicable to low level emission cases. The technique is particularly useful in investigate waste materials with a gamma emitting content which needs to be determined. The attenuation is corrected for using a bi-modal function to account for the attenuation effects arising from low and high atomic mass components of the material in which the emitters are present.

Abstract: A transport container for nuclear fuel is provided with an outer container having internal insulation, the insulation defining an internal cavity. The cavity receives a plurality of fuel containers wherein the internal volume of the fuel containers is at least 5% of the external volume of the outer container. The container allows substantially higher volume proportions of enriched fuel to be safely transported than is possible with prior containers.

Abstract: According to the present invention there is provided a method of carrying out a chemical reaction between at least two fluids, the method comprising providing respective flow paths for the at least two fluids, said flow paths communicating with each other in a region in which the at least two fluids may contact each other, and flowing the at least two fluids along said flow paths such that in said region the at least two fluids contact each other and a chemical reaction occurs between them, said region having a width perpendicular to the direction of flow in the range 10-10,000 micrometers. It has been found that using a so-called “microreactor”, that is a reactor having dimensions perpendicular to the flow direction of less than 10,000 micrometers, according to the present method, improved control over a fluid chemical reaction can be achieved, which can result in significant improvements in reaction product yield and/or purity, as well as other benefits.

Abstract: A nuclear fuel dissolution apparatus which comprises a perforated sloping ramp contained within a process chamber for containing solvent for the fuel, a pulsation member which in use creates pulses in solvent in the process chamber, the perforations being designed to direct pulses of solvent along and up the ramp, and a discharge point for fuel hulls disposed at an upper region of the ramp is characterised in that the ramp is made out of flat blades and the perforations of the ramp comprise inclined slits formed between the blades.

Abstract: The present invention provides an improved method for investing radioactive sources which takes into account variations in the materials potentially making up the samples. In particular, the invention provides a method of investigating radioactive sources in a sample, the method comprising detecting a portion of the emissions arising from the sample at an energy, the detected portion relating to a detected level, the detected being corrected according to a correction method to give a corrected level at that energy. The invention also provides improved transmission sources and improved transmission based correction techniques for use in investigating radioactive sources in a sample.

Abstract: The invention provides an improved correction technique for use in analysing bodies of material containing radioactive sources.

Abstract: Ions produced by radioactive gases present in air impact on the sensitivity of contamination measuring instruments which detect ions generated by radioactive materials present on an item. Methods and apparatus address this issue by conducting a measurement of ions generated in a chamber by gaseous emitters and other background events in a volume of medium and deducting this from a measurement of ions generated in another chamber by the item as well as the gaseous emitters and background events. The variation of the gaseous emitters present within the medium is addressed by moving the medium about. An alternative solution uses a medium free of gaseous emitters having a significant level, for instance by sealed storage of air prior to its use in a method and instrument.

Abstract: A method of removing material from a workpiece by directing a laser beam onto an area of the workpiece and at the same time injecting substantially continuously a stream of high speed (5-300 m/s) solid particles onto the area of the vicinity thereof. The solid particles may be aluminum oxide or zirconium oxide particles having a size in the range of 1-50 &mgr;m. The particle stream is preferably formed coaxially around the laser beam, the particles being accelerated by means such as an inert gas or electrostatic charge which does not work the material. The laser beam melts the material and the solid particles are directed into the molten material before exiting from the face of the material opposite that to which the stream is directed.

Abstract: A transport container for nuclear fuel is provided with an outer container having internal insulation, the insulation defining an internal cavity. The cavity receives a plurality of fuel containers wherein the internal volume of the fuel containers is at least 5% of the external volume of the outer container. The container allows substantially higher volume proportions of enriched fuel to be safely transported than is possible with prior containers.

Abstract: The contents of a container 1 are non-intrusively monitored by probing the container with an ultrasonic signal, and measuring changes in the ultrasound signature of the received signal after the signal has passed through the contents of the container.