“Right after I graduated, I interned with the Arms Control Association. It was terrific.”

– George Stephanopolous
ABC News
January 1, 2005
Iran Prepares Improved Centrifuges
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Peter Crail

Iran intends to begin its first full-scale testing of its second-generation centrifuge models, according to a Feb. 25 International Atomic Energy Agency (IAEA) report, a move that could allow Tehran to increase the rate at which it enriches uranium.

Even after the testing process, however, Iran would not be able to raise the rate significantly unless it were able to mass produce and operate new machines on a large scale. Current and former U.S. and IAEA officials said they doubted Iran maintained the capabilities to do that.

“Our understanding is that these advanced centrifuges are not yet ready for mass production,” Robert Einhorn, the Department of State’s special adviser for arms control and nonproliferation, said during a March 9 Arms Control Association briefing. “The Iranians don’t yet have sufficient confidence” in the new centrifuges to mass produce and operate them, he said.

Gas centrifuges spin at high speeds to increase the concentration of the fissile isotope uranium-235 from the levels found in natural uranium, a process called enrichment. Low-enriched uranium (LEU) commonly is used to fuel nuclear reactors while highly enriched uranium (HEU) can be used in the core of a nuclear weapon.

The IAEA report said that Iran informed the agency in January of its intention to install two 164-machine cascades of its newly developed centrifuges, called the IR-2m and the IR-4, at its pilot enrichment plant for testing. To date, Iran has tested these improved models only in cascades of up to 20 machines.

The cascades at Iran’s commercial-scale Natanz plant, where it produces its enriched uranium, operate in 164 linked machines using an older, crash-prone centrifuge model called the P-1.

An eventual move to make use of the new centrifuge models would likely increase Iran’s uranium-enrichment capacity. “The increase from 20- to 164-machine cascades for the second-generation centrifuges heightens concern that Iran may be on the edge of a breakthrough that would sharply reduce the timeline for HEU production,” Mark Fitzpatrick, former deputy assistant secretary of state for nonproliferation, said in a March 21 e-mail.

Although the performance of Iran’s newer centrifuge models is unclear, former IAEA safeguards chief Olli Heinonen indicated in a March 2 presentation that the IR-2m has about three times the potential capacity of the P-1.

Tehran obtained the P-1 centrifuge, as well as the more advanced P-2 model, from the nuclear smuggling network run by Pakistani nuclear official Abdul Qadeer Khan, who stole the designs from Europe. Both the IR-2m and IR-4 are believed to be derived from the P-2 machine. Iran developed other models based on the P-2, but has since abandoned them.

Iran’s decision to continue developing two different models of second-generation centrifuges might point to continued difficulties in their development and deployment. Fitzpatrick said that running the new designs in parallel “suggests that they have not yet ironed out all the bugs in either model.”

Heinonen said in a March 21 interview that Iran also may have decided to pursue both designs because of material constraints. He said he would not be surprised if Iran were to install both sets of machines for regular operations, expanding them as access to resources allowed.

Unlike the IR-2m, the IR-4 uses a key component called a bellows, made of carbon fiber, to connect multiple centrifuge rotors. Iranian technicians initially determined that they were unable to manufacture this sensitive part, opting instead for single-rotor machines such as the IR-2m. Iran appears to have overcome its initial difficulties in manufacturing bellows, but may still face constraints building them in sufficient numbers.

Last April, Iran unveiled what it called a third-generation centrifuge capable of enriching uranium five times faster than the P-1. Although Iranian officials said at the time that they would begin testing the machines within several months and might need a year to install a cascade, Iran has not conducted any work on this new model at its declared nuclear facilities. The February IAEA report said that Iran has not provided the agency with any information about the announced third-generation machine.

Iran has claimed to have carried out work on its P-2-based centrifuge designs intermittently since 1995, when it received the initial design and components from the Khan network. In 2006, Tehran announced that it was working on newer centrifuge models at undeclared sites, and in January 2008, it began testing these models at its pilot plant under IAEA safeguards. Since that time, Iran slowly has worked to develop and test its design modifications.

 “It’s taken quite a long time for [Iran] to graduate from the P-1’s to more advanced centrifuges,” Einhorn said at the March 9 event. He added that Iran’s delays in developing the newer machines “lengthened the amount of time in which Iran could ‘break out’ in a meaningful way,” referring to the process by which Iran might eject IAEA inspectors, leave the nuclear Nonproliferation Treaty (NPT), and build nuclear weapons.

Einhorn suggested that it would not make sense for Iran to take those actions while relying on the P-1 centrifuge, “which produces material so inefficiently.”

Heinonen agreed, stating that the P-1’s design flaws were “technically obvious” and provided a poor route for quickly producing material for nuclear weapons. He said that Iran would need both a longer time frame to enrich uranium to weapons grade and more material if it decided to use the P-1, due to the amount of waste that would occur.

In an apparent attempt to address some of its problems with the P-1, Iran has expanded 12 of the 53 installed cascades at its commercial-scale Natanz plant to hold 174 machines, rather than 164, the recent IAEA report said. Heinonen indicated that doing so would reduce the impact of centrifuge failures, which lower the enrichment levels for the cascade.

The move follows Iran’s admission last fall that the commercial-scale enrichment facility had been infected with the Stuxnet virus, widely believed to have been an industrial sabotage effort by Western countries, including the United States. (See ACT, January/February 2011.) Iran’s acknowledgment coincided with a halt to centrifuge operations for a week in mid-November.

Continued IAEA Frustration

In addition to noting Iran’s intentions regarding its improved centrifuges, the IAEA report signaled continued frustration with Iran’s lack of cooperation with the agency. The report describes itself as “focus[ing] on areas where Iran has not fully implemented its binding obligations.” Fulfillment of those obligations “is needed to establish international confidence in the exclusively peaceful nature of Iran’s nuclear program,” the report says.

An annex to the report includes a detailed list of those obligations, which are drawn from Iran’s safeguards agreement with the agency and UN Security Council resolutions.

Iran claims that the council’s demands to suspend its sensitive nuclear fuel-cycle activities are illegal and that it is cooperating fully with the IAEA investigation.

In a March 9 statement to the agency’s governing board, Iranian IAEA envoy Ali Asghar Soltanieh said that the Security Council references in the IAEA report prove Iran’s assertion that the goal of the resolutions is “the suspension of the entire nuclear fuel cycle, paving the way for the ultimate cessation of all nuclear activities in Iran.” That would deprive Iran of its rights under the NPT, he argued.

The so-called P5+1, comprising the five permanent members of the UN Security Council (China, France, Russia, the United Kingdom, and the United States) and Germany, issued a joint statement to the board the same day reaffirming their commitment to continue diplomatic engagement with Iran while calling on the country to make its nuclear activities more transparent to the IAEA. The six countries also appeared to counter Soltanieh’s claim about the council’s aims, stating, “It remains our wish to establish a cooperative relationship with Iran in many fields including that of peaceful nuclear technology—where of course we fully recognize Iran’s rights under the NPT.”

Under the NPT, non-nuclear-weapon states have broad rights to develop peaceful nuclear energy programs, but they must accept IAEA safeguards to ensure that there is no “diversion of nuclear energy from peaceful uses to nuclear weapons or other nuclear explosive devices.”

Bushehr Reactor Fuel Removed

The IAEA report also revealed that Iran intended to unload the fuel from the core of its first nuclear power reactor due to a last-minute technical hurdle that posed safety concerns.

A Feb. 28 statement by Russia’s state-run nuclear energy conglomerate Rosatom, which is responsible for the reactor’s construction and initial operations, said the fuel is being removed from the reactor because “internal elements belonging to one of the four cooling pumps were found damaged,” raising the risk that small particles could get into the reactor fuel assemblies during operations.

A diplomatic source said March 22 that the fuel unloading already had begun but that it was unclear how long it would take to unload and test the fuel.

The move is the latest in decades of delays that have plagued the reactor since its construction began near the city of Bushehr in 1975. Before this latest incident, Iran intended to begin generating electricity from the reactor April 9, coinciding with its National Nuclear Technology Day.

Kraftwerk Union, the German firm that began constructing two reactors at the Bushehr site, withdrew from the project over a payment dispute in 1979 shortly after the Iranian Revolution. Russia took over construction in 1995, but due to technical, financial, and political delays, it was unable to finish construction until the fall of 2009.

Some of the technical problems have been the result of integrating the Russian technology with the original German components. The damaged cooling pump was left over from the Kraftwerk Union project.

The timing of Bushehr’s most recent technical problems, just weeks before a series of natural disasters crippled a Japanese nuclear power plant and spread radiation from the reactors, led Iranian officials to offer additional reassurance about the safety of the Bushehr project.

When asked during a March 15 Spanish public television interview if Iran’s nuclear reactor could withstand an earthquake and tsunami similar to the ones that led to Japan’s nuclear accident, President Mahmoud Ahmadinejad insisted, “We have observed all security measures at the Bushehr nuclear plant.”