If youve flown in an aeroplane, travelled on a road, used paper, or turned on a tap supplying you with water or gas, then you may have benefited from radioisotopes produced by nuclear reactors.
This was the message from Colin Woodford and Paul Ashby on behalf of theAustralian Institute of Non-Destructive Testing presented in a paper to a recent conference held by the Australian Nuclear Association.
Non-Destructive Testing (NDT) is a widely overlooked discipline involving noninvasive and passive techniques to investigate the condition of materials and structures. Radioisotopes are commonly used in some of these procedures, and in Australia they are manufactured by the Australian Nuclear Science and Technology Organisation (ANSTO).
Mr Woodford provided an overview of how isotopes are used in Australia for such applications as smoke detectors, thickness gauging for materials such as paper and plastics, density and fill height level switches and detectors, measuring ash content and industrial radiography.
"One significant early use of radioisotopes in NDT in Australia was the use of radium for radiography of turbine blades in the early 1950s. This was undertaken by the then Electricity Commission of New South Wales under the direction of an innovative chief metallurgist, Alex Wilson. Early work such as this provided information hitherto unavailable other than by disassembly and inspection," he said.
Uses of radioisotopes has expanded to the present day where isotopes are commonly used for fixed and mobile gauging, where the density or level of a product (such as sugar, petroleum, plastics, coal, paper and cardboard) can be monitored and controlled.
"Some modern portable arm gauges now connect directly to computer programs which analyse the amount of radiation detected to produce data and graphical displays. The display may represent cross sections through pipes for wall thinning, through telegraph poles or trees for termite damage, through mooring posts for internal rot, or the checking of product density in pipes or on conveyor belts."
Small sources of Cobalt 60 are also embedded at different depths from the outer surface of a furnace. As the lining of the furnace deteriorates and collapses inwards, which is normal, the remaining thickness of refractory lining can be monitored.
Industrial radiography sometimes employs x-rays, but radioisotopes are preferred where access to pipelines, pressure vessels, or jet engines is difficult, or where availability of electrical power is not practicable.
Uses of industrial isotopes are governed by codes of practice developed by the National Health and Medical Research Council. In NSW, radiation licences issued under the Radiation Control Act 1990 by the Environmental Protection Authority typically note these codes as conditions of licence. Other States follow similar guidelines.
"Petrochemical and power generation industries are major uses of this technology. Radiography using radioisotopes is a major contributor to the maintenance of safe plant.
"NDT in all its forms permeates every aspect of our lives, often hidden or simply not acknowledged. The use of radioactive materials is an important segment of NDT and deserves to be recognised for the contribution it makes."