Special Nuclear Material
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. The definition includes any other material that the Commission determines to be special nuclear material, but does not include source material. The NRC has not declared any other material as SNM.
Where does special nuclear material come from?
Uranium-233 and plutonium do not occur naturally but can be formed in nuclear reactors and extracted from the highly radioactive spent fuel by chemical separation. Uranium-233 can be produced in special reactors that use thorium as fuel. Only small quantities of uranium-233 have ever been made in the United States. Plutonium is produced in reactors using U-238/U-235 fuel. 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 regulates two gaseous diffusion enrichment plants operated by the U.S. Enrichment Corporation.
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 some fissile material -- uranium-233, uranium-235, and plutonium-239 -- that, in concentrated form, can be 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 an atomic bomb.
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|
|SNM Licensing||10 CFR Part 70|
|Physical Protection of SNM||10 CFR Part 73|
|Material Control and Accounting||10 CFR Part 74|
|Implementation of U.S./IAEA Agreement||10 CFR Part 75|
|Gaseous Diffusion Plants (uranium enrichment)||10 CFR Part 76|