The IAEA will still be able to inspect the new facility located in an underground bunker deep inside a mountain near the city of Qom. But that hardly makes a difference. In the event Iran were to junk the non-proliferation treaty, they would kick the inspectors out anyway and be able to construct a workable bomb, probably within 6 months. That is, if they have workable bomb design and the ability to absorb the almost certain blow from either or both the US and the Israelis.

Given the nature of their new enrichment site, even our best bunker busting bombs would not be able to cause any damage to the facility.

Reuters:

A decision by the Islamic Republic to conduct sensitive atomic activities at an underground site - offering better protection against any enemy attacks - could complicate diplomatic efforts to resolve the long-running row peacefully.

Iran has said for months that it is preparing to move its highest-grade uranium refinement work to Fordow, a facility near the Shi'ite Muslim holy city of Qom in central Iran, from its main enrichment plant at Natanz.

The United States and its allies say Iran is trying to build bombs, but Tehran insists its nuclear program is aimed at generating power and for medical purposes.

"The Fordow nuclear enrichment plant will be operational in the near future," the head of Iran's Atomic Energy Organization, Fereydoun Abbasi-Davani, said.

Uranium refined to purity levels of both 3.5 percent and 20 percent can be produced at the site, he added in comments carried by Iran's Kayhan newspaper on Sunday.

Enriching uranium to the 20% level is a big deal. There are few commercial uses for uranium enriched to that level and Iran would be incapable at its current technological development to make use of it.

Instead, the 20% level is ideal because all the hard work to reach 90% enrichment - bomb grade uranium - will already have been accomplished:

In addition, they say, Fordow's capacity - a maximum of 3,000 centrifuges - is too small to produce the fuel needed for nuclear power plants, but ideal for yielding smaller amounts of high-enriched product typical of a nuclear weapons program.

Centrifuges spin at supersonic speeds, which enriches uranium by increasing the concentration of fissile isotopes.

Nuclear bombs require uranium enriched to 90 percent, but Western experts say much of the effort required to get there is already achieved once it reaches 20 percent purity, shortening the time needed for any nuclear weapons "break-out."

Iran is now daring the west to attack. And they are taking steps to insure that the guts of their program will remain beyond the reach of air strikes. Commando raids carried out at some of these underground faciltiies would seem to be the only way to destroy them. But they are heavily guarded by fanatical Revolutionary Guard troops and small, special ops raids would be difficult to mount.

Cyber warfare, assassinations, and sabotage can only take us so far. If we are serious about not allowing the Iranians a nuclear weapon, the time is growing short to realize that goal.