1. Materials capable of undergoing nuclear fission, especially uranium-235 and plutonium-239, used as fuel in nuclear reactors and weapons.
Usage: technical; usually plural; used in nuclear physics and energy contexts

Examples

• The nuclear facility carefully monitors its inventory of fissionables.
• International treaties regulate the trade and transport of fissionables.
• Enriched uranium is one of the most important fissionables in modern energy production.
• Security protocols at the plant ensure that fissionables are stored safely.
• Scientists study the properties of different fissionables to improve reactor efficiency.