The repatriation is part of a Russian-U.S. intergovernmental agreement on cooperation in returning nuclear fuel from Russian-made research reactors signed in May 2004 and a joint statement on nuclear security signed by presidents George Bush and Vladimir Putin during a meeting in Bratislava in February 2005.
Since 2004, Russia has repatriated new HEU from Soviet-built plants in eight countries: Serbia and Montenegro, Romania, Czech Republic, Bulgaria, Libya, Latvia, Poland and Uzbekistan.
Russia also completed in April 2006 repatriation of 63kg (140lb) of spent Russian-made HEU from a research reactor in Uzbekistan.
Spent nuclear fuel from all 17 reactors built by Russia's specialists outside the country is expected to return by 2012-13.
