United States Nuclear Regulatory Commission - Protecting People and the Environment
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Special Nuclear Material

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What is meant by special nuclear material?

"Special nuclear material" (SNM) is defined by Title I of the Atomic Energy Act of 1954 as plutonium, uranium-233, or uranium enriched in the isotopes uranium-233 or uranium-235, but does not include source material. The definition includes any other material that the Commission determines to be special nuclear material. The NRC has not declared any other material as special nuclear material.

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Where does special nuclear material come from?

Uranium-233 and plutonium do not occur naturally but are produced by the irradiation of source material or special nuclear material in nuclear reactors and could be extracted from used fuel or targets by chemical separation. Plutonium is produced in reactors using uranium as fuel or targets. Uranium-233 is produced in reactors that use thorium as fuel or targets. No U.S. commercial plutonium reprocessing plant is currently licensed by the NRC for operation. Uranium enriched in uranium-235 is created by an enrichment facility (see Uranium Enrichment). The NRC has issued licenses for three gas centrifuge enrichment plants and a laser enrichment test bed and previously certified two gaseous diffusion plants that are now shut down.

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Why is control of special nuclear 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."

Special nuclear material is only mildly radioactive, but it includes fissile isotopes — uranium-233, uranium-235, and plutonium-239 — that, in concentrated form, could be used as the primary ingredients of nuclear explosives. These materials, in amounts greater than formula quantities, are defined as "strategic special nuclear material" (SSNM). The uranium-235 content of low-enriched uranium can be concentrated (i.e., enriched) to make highly enriched uranium, the primary ingredient of some nuclear explosive designs. To ensure the safety of the public and the security of the Nation, the NRC regulates Material Control and Accounting programs that are maintained by facilities licensed to possess these materials.

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

Subject Code of Federal Regulations
Radiation Protection 10 CFR Part 20
Licensing of SNM 10 CFR Part 70
Physical Protection of Plants and Materials 10 CFR Part 73
Material Control and Accounting of SNM 10 CFR Part 74
Implementation of U.S./IAEA Safeguards Agreement 10 CFR Part 75

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Page Last Reviewed/Updated Tuesday, February 14, 2017