Shrugging off international concerns, Iranian President Mahmoud Ahmadinejad announced the country was moving ahead to expand its enrichment capacities by installing more advanced machinery at its main enrichment facility.
Ahmadinejad told reporters in Tehran the centrifuges are not yet operational but are five times more efficient than the model now in use at its Natanz enrichment plant.
Because enrichment can produce both nuclear weapons as well as reactor fuel, Iran is under three set of U.N. Security Council sanctions for refusing to stop its program. Its determination to expand such activities had been criticized worldwide even before an announcement earlier this month that Tehran would enrich to a higher level.
In a confidential letter to the head of the International Atomic Energy Agency, the three world powers questioned Tehran's assertion that it had started the higher enrichment project to provide fuel to a research reactor providing medical isotopes for cancer patients.
The one-page letter was significant in reflecting unified Russian and Western opposition to Iran's move. Russia in the past has often put the brakes on Western attempts to penalize Tehran for defying U.N. Security Council demands that it freeze its enrichment program, which can produce both nuclear fuel and the fissile core of warheads.
"If Iran goes ahead with this escalation, it would raise fresh concerns about Iran's nuclear intentions, in light of the fact that Iran cannot produced the needed nuclear fuel in time" to refuel the research reactor, said the letter.
Iran's decision to enrich to the 20-percent level is "wholly unjustified, contrary to U.N. Security Council resolutions and represent(s) a further step toward a capability to produce highly enriched uranium," said the letter to IAEA chief Yukiya Amano.
The 20-percent mark represents the threshold between low-enriched and high-enriched uranium.
Although warhead material must be enriched to a level of 90 percent or more, just getting its present stockpile to the 20 percent mark would be a major step for Iran's nuclear program. While enriching to 20 percent would take about one year, using up to 2,000 centrifuges at Tehran's underground Natanz facility, any next step — moving from 20 to 90 percent — would take only half a year and between 500-1,000 centrifuges.
Since its clandestine enrichment program became known eight years ago, Iran has insisted it is meant only to generate nuclear fuel. But its secrecy and refusal to cooperate with an IAEA probe of allegations that it experimented with aspects of a weapons program had increased fears about its nuclear ambitions even before President Mahmoud Ahmadinejad's Feb.7 announcement that Iran will raise the enrichment bar.