Spent Nuclear Fuel
Fuel assemblies that have been used in a reactor and are no longer efficient for sustaining a chain reaction. Spent fuel is highly radioactive and requires secure storage — initially in water pools, then in dry cask storage.
Why It Matters
The U.S. has no permanent repository for spent nuclear fuel. About 90,000 metric tons are stored at reactor sites across the country. This is a political and practical challenge, though the actual volume is small (all U.S. spent fuel would fit on a single football field stacked 10 yards high).
Related Topics
Related Terms
Nuclear Fission
The process of splitting a heavy atomic nucleus (such as uranium-235 or plutonium-239) into two lighter nuclei, releasing a large amount of energy. This is the reaction that powers all current nuclear power plants.
Uranium
A naturally occurring radioactive element used as fuel in nuclear reactors. Natural uranium is 99.3% U-238 and 0.7% U-235. Most reactors require enrichment to 3-5% U-235.