Industry

Nuclear gauges

A nuclear gauge is a device used in several construction and industrial applications to perform routine measurements quickly. The device consists of a radioactive source and detector to measure the radiation that interacts with the item being measured. When an item is placed between the source and the detector, the difference in radiation picked up by the detector can provide useful information about the item, such as its thickness, density or chemical makeup.

There are two main types of nuclear gauges.

• Fixed gauges are permanently mounted in place to analyze an industrial process. For example, they may give a continuous reading of how full a pipeline is, the density of material passing through it or the thickness of products on a conveyor belt.
• Portable nuclear gauges can be used to analyze the walls of holes that have been dug into the ground to identify mineral deposits, or to search for underground caves or other formations that could make a building site unstable.

Workplaces that use nuclear gauges in Canada do so with operating licences from the Canadian Nuclear Safety Commission, which sets strict health and safety regulations. Workers are monitored for radiation exposure from these devices and are consistently found to be among Canada’s least-exposed users of occupational radiation sources, receiving additional radiation doses far less than the average background levels.

Nondestructive testing

How do you find out how strong the ice is on a frozen lake? That’s easy if you’re willing to break it. This is the problem many industries face: the need to test or analyze products and equipment without damaging them.

There are several techniques of nondestructive testing (NDT). Two of the most common ones rely on radiation and nuclear substances.

• Industrial radiography is a portable way to verify the quality of welds during the construction and inspection of pipelines, pressurized vessels and important structural supports. It is also used for locating materials embedded inside others, such as a water or electrical conduit running through concrete. This is performed using a radiographic camera. This is a heavily shielded device that, instead of light, uses radiation from a gamma source such as cobalt-60 or iridium-192. The image can be analyzed to assess the quality of the weld, determining whether the object is safe to use.

• Neutron radiography uses a source of neutron radiation instead of gamma radiation. Portable sources for neutrons exist, but neutron radiography is usually performed at nuclear research reactors, such as the McMaster Nuclear Reactor in Hamilton, Ontario.

Neutrons interact better with organic material and water than gamma rays do, so neutron radiography is more effective at detecting corrosion and moisture-based damage. This technique is also used to verify the integrity of aircraft components, making flights safer.