|Fig. 1: Radioactive tracers being used in an industrial setting. (Source: Wikimedia Commons)|
Radioisotopes have multiple key applications in the industrial process. Radioisotopes are useful because they act like tracers in whatever substance they are added to, and can be easily measured either by electrical signal or through autoradiography (measuring nuclear emulsion). Additionally, the concentration of the substances containing tracers can be measured from outside the pipe or container the substance is held in, without touching or disturbing the substance. A guidebook created by the International Atomic Energy Agency states that nearly all industries benefit from some application of radioactive tracers. 
One common use of radioactive tracers is measuring gas leaks in industrial operations. If one gas line is not supposed to contaminate another, it can potentially be difficult to to see if the two are mixing given that gasses are often not visible to the human eye. However, if tracers are injected into both lines, detection of the tracer from one line in another is a clear indication of contamination.  Tracers can also be used as a method of quality control in hermetically sealed containers. By exposing the container to radioactive gas and measuring radioactivity inside the container, it is simple to tell if the container is properly sealed. 
Another practical application of industrial tracers is measuring flow rate of a gas or liquid. If a radioisotope is injected into the beginning of an industrial system, as shown in Fig. 1, the flow rate can be measured by how long it takes to arrive at the end of the system. More specifically the consistency of flow can be measured as well. Meaning, if the tracer exits the system in the same distribution it entered the system, the system flows at a consistent rate. If the tracer exits in a different distribution than it entered, then the system flows at an inconsistent rate. This distribution is known as the transit time distribution. 
Manufacturing metal plates is a fine process, and determining whether the resulting plate is the proper thickness throughout the entire plate can be difficult. By passing the plate through a radioactive substance and then through a measuring device, the thickness can be determined by the amount of radiation that passes through the plate. 
In a factory or other industrial setting, it important to be able to measure the rate of wear on machinery. If the machinery is lubricated, one way to measure the rate of wear is to make the machine component radioactive and measure the amount of radioactivity in the lubricating oil. This type of measurement has helped research aimed at creating better lubricating oils. If the machinery is not lubricated, the wear can be measured by the amount one radioactive component deposits onto another non-radioactive component. 
Radioactive tracers help in the process of surveying oil wells and subsequently choosing a production strategy. In order to test for fractures in an oil well or high permeability in the wall of the well, a radioactive tracer is inserted at an injection well upstream of the production output. Low levels of radioactive tracer indicate that oil is being lost at some point between the injection and output and that the well is operating at low efficiency. Tracers can also be used to measure flow rates in the well by timing how long it takes for the tracer to travel from one injection point to another. 
Radioisotopes are important in manufacturing because they allow for quick, easy, and non- interfering measurement of solids, liquids and gasses. Because of these tracers, manufacturing (mostly quality control), is cheaper and higher quality results are achieved.
© Skyler McLean. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 J. Guizerix, V. Markovic, and P. Airey, 'Radioisotopes and Radiation Technology in Industry," International Atomic Energy Agency, IAEA Bull., February 1987, p. 20.
 E. Holstein; L. Lake, Petroleum Engineering Handbook, Vol. 5 - Reservoir Engineering and Petrophysics (Society of Petroleum Engineers, 2006).