Title: Fissile Material Basics - Institute for Energy and Environmental Research
Headings: Fissile Material Basics
Fissile Material Basics
What are fissile materials?
What is plutonium-239?
How is plutonium made?
What is plutonium used for?
Where is plutonium produced?
What is highly enriched uranium?
How is highly enriched uranium made?
What is HEU used for?
Where is HEU produced?

Content: Nuclear weapons use plutonium metal. Plutonium dioxide is used as a component of some nuclear fuels. Plutonium has a half-life of over 24,000 years (a half-life is the time it takes for half of a given amount of radioactive material to decay into other elements). How is plutonium made? Two key facilities are needed to obtain plutonium. First, in a nuclear reactor, uranium-238 absorbs a neutron. This leads to nuclear reactions which convert it to plutonium. The plutonium ends up in the spent nuclear fuel along with unused uranium and highly radioactive fission products. Essentially all nuclear reactors in the world produce plutonium in this way, but plutonium in spent fuel is not usable for nuclear energy or nuclear weapons. To get plutonium into a usable form, a second key facility, a reprocessing plant, is needed to chemically separate out the plutonium from the other materials in spent fuel.