Industrial Radiography
Manufacturers use a method called industrial radiography to check for cracks or flaws in materials. Radiation is
used in industrial radiography to show problems not visible from the outside without damaging the material.

   •  Workers who use industrial radiography equipment must be trained to use it and wear special badges
      that measure their exposure to radiation.

   •  Exposure of the public to radiation from industrial radiography equipment is not likely, because the
      public is not permitted in areas where testing is conducted.

About Industrial  Radiography

Manufacturers know that consumers expect the products they buy to be safe, to work well and to last. This
reliability becomes even more important when product failure can be expensive or dangerous.

Manufacturers also use industrial radiography to check for cracks or flaws in their products. Just like medical x-
rays are used to find breaks or cracks in bones, industrial radiography uses x-rays or gamma rays to take
pictures of the inside of products because they can show problems not visible from the outside. Radiography is
useful because it does not damage or change the product being tested.

For example, industrial radiography is used to test:

   •  Gas and oil pipelines.

   •  Metal welding.

   •  Boilers.

   •  Vehicle parts.

   •  Aircraft parts.

Here's how it works: A beam of x-rays or gamma
rays is pointed at the item being tested.  A detector
is lined up with the beam on the other side of the
item. The detector records x-rays or gamma rays
that pass through the material. The thicker the
material, the fewer x-rays or gamma rays can pass
through. Because the material is thinner where
there is a crack or flaw, more rays pass  through
that area. The detector captures the rays that pass
through, which form a picture of the crack or flaw.
At right is a drawing of the parts of a special
camera, called a radiography camera, which is
used to capture radiography pictures. The pictures
from these cameras are called radiographs.
Parts of hand-held radiography camera. Such as system
typically uses radium-192 as the source of the gamma rays.
(Source: The National Research Council, National Academy
of Sciences)
  United States Environmental Protection Agency | Office of Radiation and Indoor Air (6608T) | EPA 402-F-14-008 (August 2014 |  p. 1

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The radiograph image below is an example. It shows the condition of metal around a welding site. The welding
site shows up bright white because it is thicker than the rest of the material. It has stopped the rays almost
completely from passing through. The cracks are the darker areas.
X-ray and gamma ray devices are different and used for different purposes.
                                                            Industrial radiograph: Cracks (in black)
                                                            around a pipe weld (in white).
   •   X-ray radiography devices are powered by electricity.
       When the device is turned off, x-rays are not produced.
       X-ray radiography generally creates very clear pictures.
       The devices are large and good for use in factories.

   •   The gamma rays used in radiography come from
       radioactive material inside the radiography device.
       Gamma ray devices do not need electricity. They are
       smaller than x-ray devices. Their small size makes them
       useful for checking inside pipes, ships and other small
       spaces. However, they cannot be turned off like an x-ray
       device.  The radionuclides in the device always produce
       gamma rays. The only way to "turn off" a gamma ray
       radiography device is to interrupt the beam by covering the opening with a heavy metal plate. Workers
       must be careful to close the opening when the gamma device is not in use to avoid exposure.

Rules and Guidance

U.S.  NUCLEAR REGULATORY COMMISSION (NRC)

People who want to own radiography equipment must have a license. People who want to operate the
equipment must have proper training and education to be qualified and licensed as radiographers. NRC writes
the rules for obtaining these licenses and governing the use of equipment and radiation sources. They also
write rules for the personnel involved in industrial radiography.

THE STATES
Many states have formal agreements with the Nuclear Regulatory Commission.  These agreements give states
the authority to license the use of the device as well as people who want to work as industrial radiographers.
States with this agreement with NRC are called Agreement States. However, their agreements may or may not
include industrial radiography licensing.

U.S.  DEPARTMENT OF TRANSPORTATION (DOT)

DOT writes rules about transporting radioactive sources, such as those used in portable gamma radiography
devices used in the field (for example, at construction and  cleanup sites).

What you can do

You are unlikely to be exposed to radiation from industrial  radiography equipment because the general public
is not permitted nearby when testing is conducted. However, if you are anywhere near these devices, be sure
to follow all safety rules.


Where to learn more

You can learn more about industrial radiography by visiting the resources available on the following webpage:
http://www.epa.gov/radtown/industrial-radiography.htmltflearn-more.
  United States Environmental Protection Agency | Office of Radiation and Indoor Air (6608T) |  EPA 402-F-14-008 (August 2014  | p. 2

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