Source Material

On this page:

• What is meant by source material?
• Where does source material come from?
• How is source material used commercially?
• Why is control of source material important?
• Regulations for Source Material
• Additional Information

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 can include uranium and thorium ores and the end product resulting from the 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.

Facilities processing of uranium ore in a mill to extract the uranium content are regulated as Uranium Recovery. The uranium ore concentrates will be used in the nuclear fuel cycle. 

• Ores that are processed to recover valuable metals, such as tantalum, niobium, scandium, zirconium, and other rare earths can sometimes contain uranium and thorium. These metals, and other rare earths, are used to make capacitors for cellular phones, computers, and other electronic devices. If processing of metals or rare earths results in licensable quantities and concentrations of uranium or thorium, these facilities can be regulated under the source material framework. Note the distinction between whether a facility is regulated under the source material framework or as a uranium recovery facility can depend on the processes used at a specific facility. Facilities regulated under the source material framework or the uranium recovery framework, may be overseen by the NRC or an applicable Agreement State, depending on the specific authorities delineated in the state’s agreement with the NRC.

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.

Regulations for Source Material

The NRC regulates the 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.

See also, information on all NRC Rules and Petitions.

The NRC welcomes Public Involvement in Rulemaking, and invites the public to comment on proposed rules and policies, licensing actions, and draft technical documents.  We announce public comment opportunities in the Federal Register and on our Documents for Comment page.

Additional Information

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