Nuclear 101


Module 1:


What are nuclear materials, and why are they unique?

  • The term nuclear materials commonly refers to fissile materials that are capable of sustaining a chain reaction when bombarded with slow-moving neutrons. Nuclear fission occurs when an atom of a fissile material—such as uranium-235—is bombarded with a slow-moving neutron and splits apart. When it splits, massive amounts of energy are released, as are additional neutrons that can go on to cause additional fissions in surrounding fissile materials.
  • The most commonly used fissile materials are specific variants, or isotopes, of the elements uranium and plutonium. Fissile materials are distinct from other radioactive materials such as cobalt and cesium, which cannot sustain a nuclear fission chain reaction.
  • Fission energy can be released slowly inside a reactor to generate electricity – or released all at once to produce an explosion, as with a nuclear bomb.
  • Nuclear materials, technology, and expertise associated with the nuclear fuel cycle are inherently dual-use, meaning they are useful both for the civil production of nuclear energy and the military production of nuclear weapons. Consequently, some countries try to use civil nuclear programs to disguise their pursuit of nuclear weapons.
  • Enabling the peaceful use of nuclear technology to benefit humankind without inadvertently contributing to the proliferation of nuclear weapons is a major global challenge.

What is the nuclear fuel cycle?

  • The nuclear fuel cycle refers to all industrial processes associated with using nuclear fission for peaceful or military purposes.

The Nuclear Fuel Cycle

  • The “front-end” of the nuclear fuel cycle refers to all of the processes required to acquire and prepare uranium for use inside of a nuclear weapon or nuclear reactor. It includes uranium mining and milling, conversion, enrichment, and fuel fabrication in those cases where the enriched uranium is intended to fuel any type of reactor. Module 2 explains the “front-end” of the nuclear fuel cycle in greater detail.
  • The “back-end” of the nuclear fuel cycle refers to processes that follow the removal of used or “spent” nuclear fuel from a reactor. It includes spent fuel storage, possible reprocessing of the spent fuel, which typically involves chemically separating usable plutonium from the rest of the waste, and ultimately long-term storage in a geological or other repository. Module 3 explains the “back-end” of the nuclear fuel cycle in greater detail.
  • Because acquiring enough fissile material to build a bomb is the most significant technical hurdle to achieving a nuclear weapons capability, the processes of uranium enrichment and plutonium reprocessing are considered the two most proliferation sensitive steps in the nuclear fuel cycle.