United Kingdom Atomic Energy Authority

British Gas Plc

Colin G Clayton

Ramon Spackman

Malcolm R Wormald

Lionel G Sanders

An irradiator (4) is provided for irradiating lumps of ore to detect the presence of gold in the lumps by neutron activation analysis. The irradiator (4) consists of a close packed array of three inner cylindrical ducts (14) and three outer cylindrical ducts (12) through which the lumps of ore are passed, with three neutron sources (16) arranged in the spaces between the inner ducts (14) and the outer ducts (12) to irradiate the ducts (12, 14) and to activate any gold by the reaction .sup.197 Au (n, n'.gamma.) .sup.197 Au. Each inner duct (14) is thus adjacent to two neutron sources (16), and is or larger cross-sectional area than the outer ducts (12).

Ore irradiator

A method and an apparatus are provided for measuring the flow rate of a fluid in a duct, for example in an under-sea crude oil pipeline, in which samples of a radioactive tracer are injected, at intervals, into the duct and the passage of the samples of tracer detected by a scintillator. The tracer is generated by irradiating a large volume of a liquid obtained from the environment of the duct with a neutron source, so that the sample has been irradiated for a prolonged period prior to injection.

Flow measurement

A gold sorting plant in which the gold content of lumps of ore is measured by means of a neutron activation analytical technique. Separate lumps of gold ore are graded in two sizes which are presented to an irradiator such as to irradiate them uniformly. The energized lumps of ore are conveyed to an analyzer/sorter station where the intensity of .gamma.-rays having an energy of 297 KeV from each lump of ore is measured, and it is accepted or rejected for further processing. Various forms of irradiator and analyzer/sorter are described.

Gold ore sorting

A method and apparatus are provided for analysing a fluid, especially an oil/water/gas mixture of unknown composition flowing in a pipeline (10). The apparatus can operate remotely, for example on the sea bed. A gamma-ray source (12) and a diametrically arranged scintillator (20) enable the density to be determined; while a fast neutron source (14) and a diametrically arranged germanium gamma spectrometer (22) cooled by a cryo-cooler (26) enable the concentrations of the elements present to be determined. The apparatus also includes a pulsed fast neutron source and a gamma detector to determine the flow velocity of the fluid. The apparatus enables the weight fractions of oil, water and gas to be derived.

Analysis of fluids

A method of inspecting the cover of a buried pipeline comprising the operations of irradiating the inner wall of the pipeline with neutrons from a radioactive source carried by a vehicle traversing the pipeline, measuring the intensity of ionizing radiation within the pipeline arising from nuclear interactions occuring within the cover of the pipeline and its surroundings due to the neutrons emitted by the source, and recording the measured intensity of the said ionising radiation together with data representative of the position of the vehicle along the pipeline. Apparatus for carrying out the method also is described.

Inspection of buried pipelines

Ore sorting apparatus

An irradiator for irradiating lumps of ore, to activate a selected substance in the ore by neutron activation, consists of a cylindrical chamber 10, a vibrated conical base 20 to control passage of the lumps through the chamber 10, and at least one coaxial annular neutron source 30 at one end of the chamber 10. The neutron source 30 is arranged so that all the lumps of ore are activated uniformly.

A method for determining the gold content of an auriferous material, comprising the operations of irradiating a body of the material with neutrons and determining the intensity of .gamma.-rays having an energy of 279 keV arising from the reaction .sup.197 Au (nn') .sup.197.sbsp.m Au.fwdarw.279 keV. Apparatus for carrying out the method also is described.

Analysis of gold-containing materials

A monitor for determining the ash content of coal in wagons consisting of a structure including means for irradiating each wagon as it passes the structure with a known dose of neutrons, means for detecting and measuring the intensities of .gamma.-rays emitted by ash-forming elements in the coal, and means for providing an indication of the concentration of the ash-forming elements. There also are included interlocks for ensuring that the neutron source is only operated when a loaded wagon is in the appropriate position.

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Abingdon, United Kingdom

Colin G Clayton