United States Nuclear Regulatory Commission - Protecting People and the Environment
Home > Nuclear Materials > Source Material

Source Material

On this page:

What is meant by source material?

In general terms, "source material" means material containing either the element thorium or the element uranium; provided that the uranium is not enriched in the isotope uranium-235 above that found in nature. Both natural uranium and depleted uranium are considered source material. Source material can also be a combination of thorium, depleted uranium, and natural uranium and the material can be in any physical or chemical form. Ores that contain uranium, thorium, or any combination thereof, at one-twentieth of one percent (0.05 percent) or more by weight  are source material.

Where does source material come from?

Source material includes most uranium and thorium ores and product resulting from the mining and milling processes. Source material can also be generated as a side product during the refining of ores mined for other precious metals.. Depleted uranium (material containing lower concentrations of U235 than natural uranium) is created as a by-product of the uranium enrichment process.

Source material could also be created from the reprocessing of spent nuclear fuel, but no commercial reprocessing is currently licensed in the U.S.

How is source material used commercially?

Source material is produced and processed in a variety of facility types. The first stages of the nuclear fuel cycle are represented by facilities processing source material for the ultimate use in nuclear reactors. Other source material licenses have developed industrial uses for source material. There are approximately 105 NRC-licensed source material facilities.

The following uses of source material are regulated as Uranium Recovery.

  • The mining of uranium and thorium ores
  • Uranium ore is processed in a mill to extract the uranium content. The uranium ore concentrates will be used in the nuclear fuel cycle.
  • Ores containing uranium, ore concentrates, and slags are processed to recover valuable metals, such as tantalum, niobium, scandium, zirconium, and other rare earths. These metals are used to make capacitors for cellular phones, computers, and other electronic devices. Uranium in quantities and concentrations subject to licensing are produced as a waste or by-product from these facilities.

The following uses of source material are regulated as a fuel cycle facility.

  • The uranium ore concentrates that are produced during uranium recovery are sent to a conversion facility. Here the uranium ore concentrates are purified and chemically changed to uranium hexafluoride (UF6).  The UF6 is still comprised of natural uranium.
  • The natural uranium (UF6) is then sent for enrichment. The material that is received at the plant is source material. The material that is enriched at the enrichment plant is special nuclear material. A byproduct of the enrichment process is depleted uranium; a source material.
  • Another stage in the nuclear fuel cycle that involves source material is deconversion. A deconversion plant converts depleted uranium in the chemical form of UF6 into a more stable uranium oxide. The uranium oxide (comprised of depleted uranium) are a source material.
  • A uranium downblending facility converts enriched uranium (special nuclear material) to a lower enrichment concentration using depleted uranium (source material).

The following uses of source material are regulated as an industrial-use licensee.

  • Some source material licensees use depleted uranium to manufacture industrial and military products; including shielding, armaments, and ballast.

Why is control of source material important?

Congress enacted Title I of the Atomic Energy Act of 1954, as part of President Eisenhower's Atoms for Peace program, including the clause:

"Source and special nuclear material, production facilities, and utilization facilities are affected with the public interest, and regulation by the United States of the production and utilization of atomic energy and of the facilities used in connection therewith is necessary in the national interest to assure the common defense and security and to protect the health and safety of the public."

Source material is licensed and regulated to ensure that the material is used for safe, commercial uses and is not used by adversaries. Natural uranium, a source material, contains uranium-235, a fissile material, that can be concentrated (i.e., enriched) to make highly enriched uranium, the primary ingredient of some nuclear explosive designs. Natural uranium can also be used as fuel in graphite and heavy water reactors, or as a target in a reactor to produce plutonium-239. Plutonium extracted and processed from reactor fuels or targets can be used in some types of nuclear explosives. Thorium can be used in the fuel or as a target in certain reactor designs to produce uranium-233, which is subsequently burned in the nuclear reactor or could be extracted for use in a nuclear explosive. By regulating radioactive material, while it’s still source material, prevents this material from getting into the wrong hands and undergoing any of these processes.

Misuse of nuclear materials intended for peaceful purposes to create a nuclear explosive is illegal. The NRC regulates source material to prevent misuse, to provide for the common defense and security, and to protect the health and safety of the public.

Source Material Regulations

The NRC regulates peaceful use of source material through licensing and oversight of licensee operations. Some of the regulations that pertain to source material possession or use are shown in the following table.

Subject Code of Federal Regulations
Radiation Protection Standards 10 CFR Part 20
Reporting of Defects and Noncompliances 10 CFR Part 21
Licensing of Source Material 10 CFR Part 40
Implementing US-IAEA Safeguards Agreement 10 CFR Part 75

Additional Information

See Source Material Facilities Licensing for information on the licensing of source material.

To top of page

Page Last Reviewed/Updated Thursday, December 22, 2016