The penetrating nature of radiation means it has many beneficial applications in industry, and common consumer products. A vast array of industries - from agriculture to manufacturing to computers - use radionuclide's to assess the efficiency of materials, products and processes. Irradiated silicon is also common in many household goods. Following is a brief snapshot of the ways in which nuclear technology is used by industry.
Radionuclide gauges are used in industrial processes to measure thickness, density or levels of materials during production, for example, paper, plastic film, steel sheet or surface coatings. The material passes between a radioactive source and a detector. As the intensity of the radiation is diminished by passing through the material, the strength of the detector signal can be used to measure the thickness, density or level of the material.
Measuring the level of liquid in soft drinks
Radionuclide gauges are also used to measure the level of liquid in cans of soft drink on a conveyor belt, at a rate of thousands of cans per minute.
Modern steel rolling mills could not manufacture steel plate without accurate, continuous measurement of thickness by radionuclide devices at every stage of production.
Gauging can also be used on adhesive tape, brass plating, chemicals of many types, coke and coal, detergents, floor coverings, jet engine fuel, molten aluminium, glass and scrap irons, petroleum, plastic, rubber, stainless steel, surgical adhesive, tyre fabric, vinyl wall coverings and wood chips.
ANSTO operates an irradiation facility known as GATRI, which is used to sterilise and treat a wide range of items for medical, health, industry, agriculture and research purposes.
Industrial radiography is similar to medical X-ray. It uses gamma radiation to detect structural faults in materials such as metal and concrete. Gamma radiation is also used to inspect welds and to detect cracks in pipelines by using a gamma source mounted on a remote-controlled trolley that travels inside the length of the pipe. Neutron scattering is also used in industrial materials testing and remaining life assessments. These technologies have the advantage of being non-destructive.
Aircraft and ships
Another important application made possible by the ability of radiation to penetrate matter is radiography or radiographic inspection. This well-established technique consists of taking a picture of gamma rays which pass through an object to search for defects in a casting or weld. Just as an X-ray allows a doctor to obtain a detailed picture of a bone fracture, an industrial X-ray examination permits the foundry worker to obtain a detailed picture of an internal crack in a metal casting.
In Australia, both civil and military aircraft are inspected by radiography during their regular maintenance schedules. Jet engines are checked for correct functioning by remotely exposing a radioactive source inside the engine and creating an image on a film. The exposed film can then be examined to identify any faults in the engine.
Aircraft manufacturers require radiographic inspection of all wing structure components on commercial aircraft. Similarly, shipbuilding firms require radiographic inspection of up to 10,000 welds on a single hull.
Inspecting welds in pipelines
The most frequent application of gamma radiography is the inspection of the welds in high-pressure, large diameter pipelines. A radioactive source is placed inside the pipe and the film is attached to the outside of the weld.
For examining pipelines that are hundreds of kilometres long, sophisticated, self-propelled crawlers which actually travel in and along the pipe are used. Virtually all new natural gas or oil pipeline systems are checked with this kind of radiographic inspection equipment.
Radiographic techniques are used extensively in inspecting petroleum and gas pipeline welding. The petroleum industry also uses density and liquid level radioactive gauges.
Neutrons and gamma ray techniques can be used for mineral analysis. Neutrons can interact with atoms in a sample causing the emission of gamma rays which, when analysed for characteristic energies and intensity, will identify the types and quantities of elements present. These techniques are used for online analysis in cement, mineral and coal industries. Another application is to establish the density of water in soil, such as in borehole logging, where a neutron source can be contained in a probe that can be lowered into the hole.
Gamma ray transmission or scattering can be used to determine the ash content of coal online on a conveyor belt. X-ray fluorescence is used to determine element concentrations, for example, in process streams of mineral concentrators. Probes containing radioisotopes and a detector can be immersed directly into slurry streams.
Oil, petrol and gas
Radionuclides have been used in a variety of ways in oil exploration for many years. They provide the only convenient means of locating and evaluating underground flow patterns. Radioactive material measurement can help determine the best location for an oil well and is important in reducing the costs of oil exploration.
When testing motor oils and lubricants, oil companies use radioactive tracers to measure friction wear in a petrol engine without dismantling the engine, or even stopping it. This method of measuring wear and tear is much quicker than other methods and more can be learned in a few hours than used to be possible by running an engine for a month!
Silicon chips in computers
The computer and electronic industries have high demand for high quality, precisely “doped” silicon. Irradiation of silicon ingots in a reactor accurately changes its semi-conducting properties by bombarding it with neutrons for precise periods and converting some atoms to phosphorus. The electronic properties of the silicon change with decreased resistively, make it valuable to use in high quality electronic equipment.