"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
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]
"Orphan radioactive sources or other radioactive material are sometimes unintentionally collected as scrap metal destined for recycling. Over the past decades, there have been several accidents involving such material. These accidents exposed individuals to radiation and lead to harmful environmental, social and economic impacts.
Member States need to build capabilities to search for orphan sources and deal with them safely and securely. Safety Guide No. SSG-17, Control of Orphan Sources and Other Radioactive Material in the Metal Recycling and Production Industries, provides recommendations on ensuring the safety of workers in the metal recycling industry and the public in relation to the control of radioactive material in scrap metal and metal products. The document addresses the responsibilities of the government, the regulatory body, and the industry; monitoring for radioactive material; response to the discovery of radioactive material; and management of recovered radioactive material."