In the end, there was nothing U.N. inspectors could do but watch as Iranian technicians broke open seals on the doors to a unit in Iran's nuclear program and fired up equipment that the West had hoped would remain mothballed forever.
European and American diplomats were faced with the same lack of options, trying to figure out how to stop Iran when it is determined to move ahead with a program the West fears will produce nuclear weapons.
The breaking of the seals Wednesday at the Isfahan Uranium Conversion Facility was the latest step in Iranian brinkmanship over its nuclear ambitions, which it says are peaceful, aiming only to produce electricity.
Iran rejected European proposals for limiting its program in return for economic incentives and shrugged off threats of U.N. sanctions. Europe and the U.S. backed down from that threat _ in part because it could cause a backlash prompting Iran to harden its position further, and because it's unclear if sanctions would pass the U.N. Security Council.
Instead, diplomats at the U.N. watchdog agency _ the International Atomic Energy Agency _ were debating how strongly to rebuke Iran for reopening the plant.
And Washington and Europe were placing their hopes in negotiations that Britain, Germany and France have been holding with Tehran. Iranian President Mahmoud Ahmadinejad said Tuesday that he would make new proposals soon.
But the resumption of operations at the Isfahan plant is a signal that Iran is serious in saying it won't give up its program to process uranium into nuclear fuel.
The Isfahan facility carries out an earlier step in the process, converting yellowcake _ raw uranium _ into uranium hexaflouride gas, UF-6, the feedstock that in the next stage is fed into centrifuges for enrichment.
Iran notified the IAEA Tuesday that it wanted the Isfahan seals removed, saying either the agency could do it, or Iranian officials would remove them under IAEA supervision.
Before the November suspension, the Isfahan facility converted some 37 tons of yellowcake into UF-4, a preliminary stage. Experts say that amount could yield 200 pounds of weapons-grade uranium, enough to make five crude nuclear weapons.
The removal of the seals Wednesday means the facility can start converting that UF-4 to UF-6, as well as convert more yellowcake from scratch.
_ Information from the Associated Press and the New York Times was used in this report.
IRAN RESUMES NUCLEAR PROGRAM
Still insisting its nuclear program is for electricity, Iran on Monday resumed uranium conversion activities at its Isfahan facility.
HOW URANIUM IS ENRICHED
An enrichment facility creates fuel for nuclear reactors _ or bombs _ by increasing the amount of unstable atoms a mass of uranium contains.
TWO ISOTOPES ( TYPES) OF URANIUM
U238: Heavier, more stable atoms
U235: Lighter, less stable uranium atoms
MACHINE FOR ENRICHING URANIUM
Enrichment plant uses high-speed centrifuges that spin uranium gas, separating U238 and U235
1. Uranium turned into gas
2. Pumped into spinning metal cylinder
3. Gas containing U235 pumped into another centrifuge
4. Hundreds of centrifuges linked in a "cascade'
KEY DATES IN THE NUCLEAR STANDOFF
FEBRUARY _ MAY 2003
International Atomic Energy Agency examined nuclear facilities in Iran
IAEA said Iran kept certain nuclear activities secret and urged Tehran to allow more inspectionsOCTOBER
Iran agreed to stop enriching uranium
IAEA said Iran admitted producing weapons-grade uranium, but found no evidence of a weapon
Iran signed the Additional Protocol in Vienna
Media reports said Pakistani scientist delivered nuclear weapons technology to Iran
IAEA urged disclosure of all plans concerning Iran's nuclear program by June
Iran's report was criticized by the U. S. government
U. S. Secretary of State Colin Powell called for international sanctions
Iran said it would resume uranium conversion at Isfahan
Britain, France and Germany warned Tehran of consequences if they broke off talks
Iran reasserted its right to develop peaceful nuclear technology
Tehran announced it resumed uranium conversion; IAEA called an emergency meeting
Sources: USEC Inc., Bulletin of the Atomic Scientists, Encyclopaedia Britannica, The Making of the Atomic Bomb by Richard Rhodes; GlobalSecurity. org; DigitalGlobe