Depleted uranium
Depleted uranium is widely available as a feedstock. Stockpiles in the United States currently contain approximately 700,000 metric tons, which is a byproduct of the enrichment process. TerraPower has estimated that the Paducah enrichment facility stockpile alone represents an energy resource equivalent to $100 trillion worth of electricity. TerraPower has also estimated that wide deployment of TWRs could enable projected global stockpiles of depleted uranium to sustain 80% of the world's population at U.S. per capita energy usages for over a millennium.