From the AP:

The U.N. atomic agency has found traces of highly enriched uranium at an Iranian site linked to the country’s defense ministry, diplomats said Friday. The finding added to concerns that Tehran was hiding activities that could be used to make nuclear arms.

The diplomats, who demanded anonymity in exchange for revealing the confidential information, said the findings were preliminary and still had to be confirmed through other lab tests. But they said the density of enrichment appeared close to or beyond weapons grade _ the level used to make nuclear warheads.

We learn something else through UPI:

The discovery marked the third instance that highly enriched uranium was found at an Iranian facility, but the IAEA said the nuclear fingerprint on the new discovery does not match that found on earlier samples, which the agency had concluded came from contaminated equipment from Pakistan, The New York Times reported Friday. 

Folks, it takes at least about 2% U-235 enriched nuclear fuel to make a nuclear reactor function (i.e., stay critical and produce power), and this value usually doesn’t go above about 5% (except for military reactors, that is, the types on board submarines, which are highly enriched for reasons that I won’t go into here).  But commercial nuclear power simply doesn’t need fuel above about 5% U-235.  The rest of it is U-238.  Something else happens to the U-238.  It absorbs a neutron to become Pu-239 which is fissile with a “thermal” neutron, and ends up producing power due to fission later on.  Pu-239 is fissile while U-238 is not — it is “fissionable,” which means it cannot fission from a neutron below 1 MeV.  What is the upshot of this?  U-238 cannot be used to make a bomb.  You have to enrich the mixture to increase the U-235 content.

When they say “highly enriched,” they mean much greater than 90% (>> 90%).  This enrichment does not work for anything except naval reactors (the technology for these reactors is not available to Iran) and nuclear bombs.

I hope this is clear to everyone.  Reactors for submarines that the Iranians do not know how to build, and nuclear bombs.  These are the only reasons a country needs highly enriched Uranium.

And what we learn from the IAEA is that the signature (characteristic gammas) of this Uranium ensures that it did not come from Pakistan where the original contamination came from years ago.  This is different Uranium from a different source.

Hold on to your shorts and tighten your seat belts.  Here we go.