The Megatons to Megawatts program was initiated in 1993 and completed on schedule in December 2013. A total of 500 tonnes of Russian warhead grade HEU (equivalent to 20,008 nuclear warheads) were converted in Russia to nearly 15,000 tonnes tons of LEU (low enriched uranium) and sold to the US for use as fuel in American nuclear power plants. The program was the largest and most successful nuclear non-proliferation program to date. The first nuclear power plant to receive low-enriched fuel containing uranium under this program was the Cooper Nuclear Station in 1998. During the 20-year Megatons to Megawatts program, as much as 10 percent of the electricity produced in the United States was generated by fuel fabricated using LEU from Russian HEU.