WASHINGTON -- U.S. officials have insisted for a decade that getting plutonium or highly enriched uranium is the big hurdle for rogue states or terrorists trying to build nuclear weapons. But for much of that time, they've known a secret: Other materials can be used to make atomic bombs, and they're a lot easier to get.
Now, officials believe the bad guys know the secret too.
Classified nuclear threat reports warn that rogue countries and terrorists have learned it is possible to make atomic bombs using low-enriched uranium, a common fuel for nuclear reactors used to conduct research and generate power. The reports, described to USA TODAY by top federal officials, also conclude that it would be easier than previously believed for enemies of the United States to make such weapons using spent nuclear fuel, the waste generated by reactors.
Neither of those substances is listed as ''weapons usable'' under U.S. or international security protocols. As a result, they get little protection from theft at civilian nuclear reactors worldwide. That includes reactors in former Soviet states and nations such as Indonesia, where public sympathy runs high for Iraq and al-Qaeda.
And the threats are real.
Five years ago, U.S. scientists at Los Alamos National Laboratory secretly designed an atomic bomb with low-enriched uranium, USA TODAY has learned. The bomb, which could have fit easily in a small pickup, was weak in nuclear terms but strong enough to destroy a square mile of a city.
U.S. scientists also have proved in experiments that it is possible to create nuclear weapons using several elements that could be extracted from spent fuel by a rogue state or perhaps even a well-organized terrorist organization.
Officials stress that there is no evidence that al-Qaeda or any other terror group has the skills or tools to build an atomic bomb using low-enriched uranium or spent fuel. There's a big gap, they say, between knowing such things are possible and being able to do them. Rogue states are a bigger concern: U.S. officials believe that Iran and North Korea are trying to develop the capability to make nuclear weapons using spent fuel. . . .