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: Uranium-235 occurs in nature. For all practical purposes, plutonium-239 does not. What is plutonium-239? Plutonium-239 (hereafter referred to as “plutonium”) is a heavy element consisting of 94 protons and 145 neutrons. It can have a number of chemical forms. 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.