When the natural uranium is mined from underground and open pit mines, it consists of 99.3 % U-238 and only 0.7% of U-235. The extracted ore goes through the ordinary mineral dressing processes (crushing, grinding, screening, flotation, and gravity separation) to increase the U-235 concentration. It is then chemically processed to form "yellowcake" (U₃O₈). Then, uranium hexafluoride gas (UF₆) is produced by fluorination of U₃O₈. As a gas, it undergoes enrichment to increase the U-235 content from 0.7% to about 3.5%. It is then turned into a hard ceramic oxide (UO₂) for assembly as reactor fuel elements.

The nuclear fuel consists of cylindrical pellets of compacted UO₂ in 3 to 4 meter long and about 0.1 m in diameter zircaloy tubes. Approximately, one pellet of UO₂ will generate energy equivalent to one ton of coal. About 30 to 60 fuel rods are bundled to form a fuel assembly.

The fuel rods in the nuclear reactor generated heat through nuclear fission. When a neutron is absorbed into a U-235 atom, it becomes an unstable U-236. By electric repulsion, U-236 splits into fission products (ex. Barium, Krypton, and etc.). The binding forces are converted into energy in the form of heat and Gamma radiation. When this reaction occurs under controlled environment, two free neutrons will be available for continued fission processes.

A 1-MW nuclear power plant typically contains about 100 tons of uranium fuel. Once a year, about one-third of the fuel rods are removed and replaced with fresh fuel. The spent fuel rods are composed of about 94% of U-238, U-235, radioactive fission products, and other radioisotopes. Although they represent a small proportion of the spent fuel, only 3.5%, they are highly radioactive and continue to generate heat and release radiation long after the fuel is removed from the reactor. Most spent fuel from nuclear power plants is stored in pools of water at the reactor site, temporarily. The water works as a coolant and radiation shield.

United States policies governing the permanent disposal of high-level radioactive waste are defined by the Nuclear Waste Policy Act of 1982 as amended. This act specifies that high-level radioactive waste will be disposed of underground, in a deep geologic repository and that Yucca Mountain, Nevada, will be the single candidate site for characterization as a potential geologic repository. This act provides for a procedure and timetable for the site selection, construction, and operation of HLW mined geologic repositories.

• Uranium Fuel Cycle



• Nuclear Organizations
  • The American Nuclear Society (ANS) is a not-for-profit, international, scientific and educational organization established by a group of individuals who recognized the need to unify the professional activities within the diverse fields of nuclear science and technology.
  • The International Atomic Energy Agency (IAEA) serves as the world's central intergovernmental forum for scientific and technical cooperation in the nuclear field, and as the international inspectorate for the application of nuclear safeguards and verification measures covering civilian nuclear programs.
  • The Nuclear Energy Institute (NEI) is the policy organization of the nuclear energy and technologies industry and participates in both the national and global policy-making process.
  • The World Nuclear Association is the global industrial organization that seeks to promote the peaceful worldwide use of nuclear power as a sustainable energy resource for the coming centuries.