I don't care WHAT Holdren's credentials are IF he said that someone can make a nuclear weapon out of 3% enriched reactor fuel; then he is just PLAIN WRONG!!!.
However, I doubt that Holdren actually said something like that because it is STUPID.
More likely, someone has TWISTED and DISTORTED something that Holdren said into the FALSE statements above.
Since you NEVER give us direct quotes by people; we only get third or fourth hand accounts; and then the statement is claimed accurate because of the credentials of the original author; independent of how the statement has been MORPHED and DISTORTED into something else.
But the clear scientific FACTS are that 3% enriched uranium reactor fuel can NOT be used to make a nuclear weapons, and practically all Physicists know that!
http://en.wikipedia.org/wiki/Nuclear_weapon_design
Little Boy, the Hiroshima bomb, used 141 lb (64 kg) of uranium with an average enrichment of around 80%, or 112 lb (51 kg) of U-235, just about the bare-metal critical mass.
where as nuclear power reactor fuel is 3% to 5%:
http://en.wikipedia.org/wiki/Enriched_uranium#Low-enriched_uranium_.28LEU.29
Low-enriched uranium (LEU) has a lower than 20% concentration of 235U. For use in commercial light water reactors (LWR), the most prevalent power reactors in the world, uranium is enriched to 3 to 5% U-235
If Holdren says that 5% LEU can be used as the fuel for a nuclear bomb; then he is STUPID.
But I doubt he said that. He is just being MISREPRESENTED as saying that.
PamW