Russian officials admitted that in the last decade, 5-10 pounds of enriched uranium and several ounces of weapons grade of plutonium had been stolen from their nuclear power facilities. Some of this stuff has been discovered, in small quantities, in Western Europe, Turkey and Russia as the thieves sought to sell it. The amount the Russians admit to losing is not enough to make a bomb, and much of the missing stuff could be accounting and handling errors (both common in the Russian bureaucracy.)