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Orphan source

An orphan source is a self-contained radioactive source that is no longer under proper regulatory control.

The United States Nuclear Regulatory Commission defines an orphan source more exactly as:[1]

...a sealed source of radioactive material contained in a small volume--but not radioactively contaminated soils and bulk metals--in any one or more of the following conditions
  • In an uncontrolled condition that requires removal to protect public health and safety from a radiological threat
  • Controlled or uncontrolled, but for which a responsible party cannot be readily identified
  • Controlled, but the material's continued security cannot be assured. If held by a licensee, the licensee has few or no options for, or is incapable of providing for, the safe disposition of the material
  • In the possession of a person, not licensed to possess the material, who did not seek to possess the material
  • In the possession of a State radiological protection program for the sole purpose of mitigating a radiological threat because the orphan source is in one of the conditions described in one of the first four bullets and for which the State does not have a means to provide for the material's appropriate disposition

Orphan sources in the real world

Most known orphan sources were, generally, small radioactive sources produced legitimately under governmental regulation and put into service for radiography, generating electricity in radioisotope thermoelectric generators, medical radiotherapy or irradiation.[citation needed] These sources were then "abandoned, lost, misplaced or stolen" and so no longer subject to proper regulation.[2]

For example, in different incidents, various orphan sources have been:

  • stolen from an RTG in a Russian lighthouse and then recovered 50 kilometres away at a bus station (Leningrad, Russia, 1999)[3]
  • lost during radiography and taken home by other people who initially failed to recognise the source (Morocco, 1984)[4]
  • lost during radiography at a power plant and found by an unsuspecting worker who put the source in his chest pocket (Gilan, Iran, 1996)[5]
  • taken home by the person who found the source after it was lost (Meet Halfa, Egypt, 2000)[6]


  1. ^ NRC: Orphan Sources
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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Orphan_source". A list of authors is available in Wikipedia.
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