An Orphan source

Today I learned what an orphan source is.

Orphan source
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An orphan source is a self-contained radioactive source that is no longer under 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
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]

See also

List of orphan source incidents

“NRC: Orphan Sources”. Retrieved 2014-03-05.none
[1] Archived October 1, 2004, at the Wayback Machine