Uranium converted from Russian nuclear warheads has provided an estimated 10 percent of U.S. electric power in recent years. The 20-year "Megatons to Megawatts" program has come to an end.
Americans once lived in fear of the Soviet nuclear missiles that were aimed at them.
For the past two decades, however, almost 20,000 of those Russian warheads have provided highly enriched uranium. It was converted to low-enriched uranium that America's nuclear power plants have used as fuel.
The "Megatons to Megawatts" program is the result of a 1993 agreement between the two countries, in which Russia turned 500 metric tons of weapons-grade uranium to fuel for nuclear power plants and sold it to U.S. commercial energy producers for a total of $17 billion.
The final shipment arrived this week in the port of Baltimore, Maryland, from St. Petersburg, Russia.
The uranium provided seven trillion kilowatts of energy - enough to light the entire United States for two years.
At the Russian embassy in Washington, both countries celebrated the long-running partnership, which U.S. Deputy Energy Secretary Daniel Poneman called "the most successful nonproliferation agreement in the history of the world." He said more joint projects are to come.
"We are now talking about how to build on the new measures we've put into place to establish a new baseline for further cooperation," he said.
Russia and the United States will work together on nuclear technology, atomic energy, and helping other countries dispose of their nuclear materials.