United States Nuclear Regulatory Commission - Protecting People and the Environment
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Nuclear Materials

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Regulated Materials

  • Special Nuclear Material consists of uranium-233 or uranium-235, enriched uranium, or plutonium

  • Source Material is natural uranium or thorium or depleted uranium that is not suitable for use as reactor fuel

  • Byproduct Material, in general, is nuclear material (other than special nuclear material) that is produced or made radioactive in a nuclear reactor. Byproduct material also includes the tailings and waste produced by extracting or concentrating uranium or thorium from an ore processed primarily for its source material content.

For details regarding the types of materials regulated by the U.S. Nuclear Regulatory Commission (NRC), see Regulation of Radioactive Materials.

Regulated Activities

For general information, see How We Regulate. For details, see the following related pages:


Of the more than 20,000 active source, byproduct, and special nuclear materials licenses in place in the United States, about a quarter are administered by the NRC, while the rest are administered by the 37 Agreement States.

The NRC's Office of Nuclear Material Safety and Safeguards (NMSS) regulates activities that provide for the safe and secure production of nuclear fuel used in commercial nuclear reactors; the safe storage, transportation, and disposal of high-level radioactive waste and spent nuclear fuel; the transportation of radioactive materials regulated under the Atomic Energy Act of 1954; develops and oversees the regulatory framework for the safe and secure use of nuclear materials; medical, industrial, and academic applications; uranium recovery activities, low-level radioactive waste sites; and the decommissioning of previously operating nuclear facilities and power plants. The agency's four regional offices (Region I - Northeast, Region II - Southeast, Region III - Midwest, and Region IV - West/Southwest) implement the NRC's materials program in the States for which they are responsible. Materials regulation is also supported by independent advice from the Advisory Committee on the Medical Uses of Isotopes.

The NRC ensures that its materials program complies with the National Environmental Policy Act (NEPA) by conducting NEPA reviews for all major actions within the program. See Materials Environmental Reviews for detailed information on active reviews.

Page Last Reviewed/Updated Tuesday, June 30, 2015