Iran seems determined to build nuclear weapons. The IAEA - the world's nuclear policeman - seems unable to stop it, writes Lara Marlowe.
Three huge ambiguities and 18 years of secrecy lie at the heart of the long-running crisis over Iran's nuclear programme.
The first ambiguity is the Non-Proliferation Treaty (NPT) itself. The Iranian government believe that article IV of the 1970 agreement gives them the right to master the nuclear fuel cycle - in other words to enrich uranium.
"Nothing in this treaty shall be interpreted as affecting the inalienable right of all the parties to the treaty to develop research, production and use of nuclear energy for peaceful purposes . . ." the treaty says.
An official at the International Atomic Energy Agency (IAEA) said off the record that as a signatory to the NPT, Iran is entitled to enrich uranium and build a heavy water reactor - precisely the two things that the IAEA's board of governors asked Iran not to do in a resolution passed by 22 of 35 governors on September 24th. "We are trying to persuade them to go beyond the NPT and the Additional Protocol," the official said. "It's voluntary transparency."
The United States and the so-called E3 (Britain, France and Germany; E is for Europe), who negotiated unsuccessfully with Iran for the past two years, stress Iran's "history of concealment" and the "resulting absence of confidence that Iran's nuclear programme is exclusively for peaceful purposes".
The words are taken from the September 24th resolution. It stopped short of sending Iran to the Security Council, but said the case is "within the competence of the Security Council". The issue will flare up again when the IAEA board meets next month.
Experts are divided on Iran's right to enrich uranium. The majority of the 31 countries with nuclear power programmes import their nuclear fuel.
Dr Bruno Tertrais, a senior research fellow at the Fondation pour la Recherche Stratégique, says the widespread availability of reactor fuel means Iran can realise its right to nuclear energy without enriching fuel. "The NPT is short and fuzzy," Tertrais says. "Nothing in it says 'right to fuel cycle'. Nothing in it says 'enrichment capability'."
Georges Le Guelte spent 30 years at the French atomic energy commission and four years as the IAEA. He is now a research director at the Institut de Relations Internationales et Stratégiques. "Under the treaty, the Iranians have the right to do what they are doing," Le Guelte says.
"But there is no rationale behind it (other than a military programme). When you buy a car, you don't buy a refinery to get your fuel. If their programme was for purely peaceful purposes, why didn't they report it to the IAEA? We cannot have confidence in what they say because they hid everything."
Energy has been a sensitive issue between Iran and the West since the British discovered petroleum in Khuzistan in 1908. Over the next 43 years, until the democratically-elected prime minister, Mohammed Mossadegh, nationalised the oil company in 1951, the British took most of the profits and refused to share technology with the Iranians. In 1953 US and British intelligence organised the coup that toppled Mossadegh.
When the Shah started Iran's nuclear power programme in 1973, western governments clamoured to sell him nuclear reactors and enrichment technology. The Bushehr reactor on the Persian Gulf was started by the German company, Siemens, in 1974. "The Shah had just signed the NPT, and he gave television interviews saying he didn't see why Iran shouldn't have nuclear weapons, since the US and USSR did," Georges Le Guelte recalls.
When the 1979 revolution swept Ayatollah Khomeini to power, he stopped the nuclear programme, calling it "the work of the devil". But Iraq invaded Iran the following year, with the active support of the US and Europe. Scud missile and chemical weapons attacks convinced the clerical regime they might need nuclear weapons against Saddam Hussein. In 1985 Iranian scientists resumed work on the nuclear programme.
That is where the second ambiguity comes in. "There is absolutely no difference between a civilian programme and a military programme, because most of the installations can be used for either," says Bruno Tertrais.
The IAEA is still trying to establish a chronology for what happened between 1985 and 2003. Iran conducted secret laboratory experiments on uranium enrichment and plutonium separation, but the most significant development was the purchase of centrifuge plans and parts from Pakistani nuclear scientist Abdul Qadeer Khan.
"If we had a time machine and we could go to the Netherlands in the 1970s and pluck Abdul Qadeer Khan out of the Urenco plant and tell him, 'You're going to be an actor, not an engineer', the world would be a safer place," laughs Bruno Tertrais. Urenco is a British, Dutch and German consortium that enriches uranium for use as fuel in nuclear power plants. Khan walked away with a suitcase full of design documents and plenty of first-hand knowledge.
He gave Pakistan the ability to enrich uranium, and the bomb. He sold enrichment technology to North Korea, Libya and Iran.
"We don't know if Khan sold the Iranians a bomb plan," Tertrais says. "Gadafy gave the IAEA a complete blueprint of Chinese origin for a nuclear warhead. It was delivered to the Libyans in an Islamabad laundry bag."
Until Gadafy renounced his own nuclear programme, no one suspected that Khan sold components for 500 P-1 centrifuges, and plans for P-1s and P-2s, to Iran. The 'P' stands for Pakistan. "P-1s are like 1950s cars," says an IAEA source, "superseded by more advanced and reliable models." The P-1s tend to break with use, while the more modern P-2s are made of super-strong "maraging" steel.
Iran built hundreds of P-1s from Khan's plans, mostly at the Kalaye Electric Company in Tehran. One of the contentious issues the IAEA is still trying to clear up is whether Iran has built P-2s.
A centrifuge is a two-metre high cylinder, about 15 to 20cm in diameter, which spins at the speed of sound to separate heavier uranium 238 isotopes from infinitesimally lighter uranium 235. Centrifugal forces cause the lighter atoms to collect at the centre of the cylinder while heavier ones are thrown to the outer edges of the tube.
Uranium 235 is the ideal fissile material for a nuclear warhead. It is also the crucial ingredient for fuel rods for power plants. For fuel rods, you need low enriched uranium (LEU) of up to 5 per cent U235; for a warhead, it must be highly enriched uranium (HEU) - at least 90 per cent U235.
To obtain U235 you put UF6 (uranium hexafluoride) gas into a "cascade" or series of centrifuges. The process is more difficult than it sounds.
UF6 is corrosive and must be stored under high pressure in strong metal containers at around 80 degrees centigrade to remain a gas. The more often you put it through the centrifuge cascade, the higher the level of enrichment.
In November 2004 Iran agreed to suspend enrichment activities while negotiating with the E3. Last spring the Europeans rejected an Iranian offer to dismantle the industrial-scale enrichment plant at Natanz and keep only a small research facility under strict IAEA surveillance. The Europeans agree with President Bush that "we can't trust the Iranians when it comes to enriching uranium . . . they should not be allowed to enrich uranium".
Iran's belief in what it calls its inalienable right to enrich uranium was sure to collide with the US and European Union demand for a permanent end to the process. In August, Tehran announced that it would resume enrichment, and called in IAEA inspectors to witness the breaking of seals at the Isfahan uranium conversion facility. For the time being Iran is only converting so-called yellowcake uranium ore concentrate into UF6 gas. The real showdown will occur when they begin feeding gas into centrifuges for enrichment.
The Iranian nuclear programme only came to light because the Mujaheddin Khalq, an opposition movement which the US State Department still calls a "terrorist group", revealed in August 2002 that Iran had built an enrichment plant at Natanz and a heavy water plant at Arak. A small US think tank identified the installations on images from a commercial satellite company.
Six months passed before the IAEA was allowed to inspect them.
At Natanz the IAEA found a "cascade" of 164 P-1 centrifuges. The Iranians say the Arak heavy water reactor is for medical research. It will not come online until 2014. Although it could produce weapons grade plutonium, at this stage it worries experts far less than the enrichment capability.
Writing in the French newspaper Le Monde, Francois Nicoullaud, who retired as France's ambassador to Tehran in July, said that nearly two decades of clandestine Iranian experiments yielded only a few milligrams of plutonium and a few grams of 1 per cent low enriched uranium, while a warhead would require seven kilos of plutonium or 20 to 25 kilos of 90 per cent enriched uranium.
One may, nonetheless, ask why Tehran was attempting to produce fissile material, ostensibly for reactor fuel, when it has no nuclear power reactors. Russia will complete the Bushehr power plant next year, but Moscow will provide the nuclear fuel for Bushehr and remove spent fuel rods to ensure there is no diversion to a military programme.
A report issued by the respected International Institute of Strategic Studies (IISS) in London on September 6th concluded it is unlikely that Iran had undeclared stocks of fissile materials, or that it was hiding installations capable of producing such materials.
When IAEA inspectors earlier found traces of highly enriched uranium from swipes at the Kalaye Electric Company, the Bush administration thought it had found the smoking gun. Tehran said the traces were contamination left by the Pakistanis on centrifuges they sold to Iran.
John Bolton, who was then in charge of nuclear issues for the Bush administration and is now US ambassador to the United Nations, told Congress the Iranians were lying. In August an international panel of scientists, which included US government experts, corroborated the Iranian story, based on samples provided by Pakistan.
But suspicions linger. The IAEA has been asking for at least a year to visit Parchin, where the Mujuheddin Khalq claim Iran is working on weaponisation. Inspectors were allowed to tour part of the complex in January, but were kept out of another section. In March 2004 six buildings at Lavizan-Shian, another site indicated by the Mujaheddin Khalq, were destroyed and several metres of soil were removed before an IAEA inspection which had been postponed for five weeks by the Iranians.
In his September 2nd report Mohamed ElBaradei, the director general of the IAEA, also questioned why Iran has experimented with polonium-210 and attempted to acquire beryllium metal.
Together, the two elements can be used as a neutron initiator in nuclear weapons.
If Iran installs 1,000 centrifuges (which it is already believed to possess) at Natanz, the plant could produce between nine and 10 kilos of high-enriched uranium each year, the IISS reported. At that rate, it would take two to three years to obtain enough for one warhead. Israel claims Iran could make a bomb within six months; a US intelligence report leaked this summer estimated it would take five to 10 years.
Iran's intentions, and the IAEA's inability to deliver a definitive judgment, is the third ambiguity surrounding the nuclear programme.
Throughout his agency's efforts to push and prod Iran to co-operate, ElBaradei has maintained that there is no evidence that Iran is pursuing nuclear weapons. Yet his September 2nd report and the September 24th resolution note that "the agency is still not in a position to conclude that there are no undeclared nuclear materials or activities in Iran".
Is it conceivable that Iran pursued a secret programme for 18 years for purely peaceful purposes? Conceivable, but unlikely, experts agree.
"The Iranians give the impression they are exploring all possibilities, that they want to keep all technical options open," says Bruno Tertrais. The primary motivation, he believes, is influence, status and prestige, followed by a desire to deter US military aggression.
"The Iranians want to have their cake and eat it," Tertrais continues.
"They want to be in the NPT and develop the bomb. They say they want to be [ like] Japan (which has mastered the fuel cycle but does not produce weapons), but I think they want to be [ like] India (which has nuclear power and nuclear weapons). They think they will get away with it, because the international community has accepted that India has nuclear weapons."
A draft law currently before the Iranian Majlis (parliament) would suspend Iran's observance of the Additional Protocol to the NPT, which allows surprise inspections by the IAEA, until Iran completes the fuel cycle.
On September 20th Iran's chief negotiator Ali Larijani warned the IAEA against referring Iran to the Security Council. "If they want to use the language of force," he said, "Iran will have no choice but to leave the framework of the NPT and the Additional Protocol and resume enrichment to preserve its technical achievements."
The game of threat and counter-threat continues. If Iran withdraws from the NPT, as North Korea did in 2003, it would sound the death knell of the treaty and could trigger a nuclear arms race with Egypt, Syria, Saudi Arabia and Turkey. North Korea was dragged before the the Security Council, but no concrete action followed, and Pyongyang is now believed to have up to six nuclear warheads.
Recourse to military strikes was discounted by the British foreign secretary, Jack Straw, on September 29th, though Mr Bush says it is still an option. At best, the IISS report concluded, attacks on Iran's nuclear installations would slow the programme.
At worst, they could lead to war.