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. Last Updated: 07/27/2016

Scientists Say Atomic Research by Iran Is Risky

NEW YORK -- There are times when even a little bit of research can be a bad thing, especially if it centers on Iran and the bomb.

On Tuesday, a wide range of nuclear scientists and analysts faulted as dangerous Moscow's tentative proposal to let Tehran do small amounts of research on uranium enrichment, with some comparing it to being a little bit pregnant.

"After a while, you tend to wind up having a baby," said Peter Zimmerman, a professor of science and security in the war studies department of King's College, London. "I do not believe the Iranians should have any access to enrichment technology until they prove to be a more responsible partner than they've been so far.''

The Iranians have strenuously objected to such characterizations, saying the West wants to deprive them of atomic knowledge and expertise that they have a right to acquire for a peaceful program of nuclear power.

They see it as nothing less than a devious plot by outside powers to keep their country from modernizing. In an interview with al-Arabiya television last month, for example, Ali Larijani, Iran's top nuclear negotiator, said, "The problem is that they look at the Islamic nations as being inferior, that we should not have modern technology, and it is enough for us to produce tomato paste and mineral water."

On Monday, European officials described a Russian proposal in which Iran would agree to a moratorium on production of enriched uranium on an industrial scale but would eventually be allowed to pursue what it calls its small-scale "research and development." On Tuesday, Russian officials denied that the proposal had ever circulated. But officials think the idea is certain to resurface.

The proposal as described appears to refer to Iran's work at Natanz, where it is building a prototype plant that would hold 1,000 centrifuges and an industrial-scale one that would hold 50,000 machines. Centrifuges are tall, thin devices whose rotors spin extraordinarily fast to enrich a toxic gas in uranium's rare component, uranium 235, which can then be used to fuel nuclear reactors or atom bombs.

The nuclear scientists and analysts said the research plant of 1,000 centrifuges would pose no immediate threat of weapon making if it were enriching natural uranium. To enrich enough natural uranium for a single nuclear warhead, they said, the plant's 1,000 centrifuges would have to operate around the clock for two or three years.

But the calculus would change significantly, they said, if Iran acquired uranium that had already undergone some minimal enrichment and fed that into the prototype plant.

On the face of it, that sounds like an exaggeration. After all, nuclear reactors operate on fuel containing only about 4 percent uranium 235, whereas nuclear weapons require levels of 90 percent or higher. Thus, Iran's diverting fuel for a nuclear reactor into the research plant would seem to give it hardly any advantage in making nuclear arms.

Not so, the analysts said. They explained that enrichment works under laws that are highly complex and nonlinear. Thus, it takes more energy to enrich natural uranium to a level of 4 percent than it does to go from 4 to 90 percent.

For Iran's research plant, that kind of nonlinearity could translate into a great reduction in the time needed to produce a bomb.

The International Institute for Strategic Studies, a respected arms analysis group in London, has calculated that the 1,000 centrifuges, if spinning low-enriched uranium, could make fuel for a bomb not in years but in as little as 108 days.

David Albright and Corey Hinderstein of the Institute for Science and International Security, a private research group in Washington, have found that as few as 500 Iranian centrifuges spinning low-enriched uranium could produce weapons-grade fuel for a bomb in just six months.

Could Iran, if it had international approval to go ahead and do centrifuge research, also gain access to a supply of low-enriched uranium, clandestinely or otherwise?

The analysts said that was quite possible. Iran already has a number of research reactors running on low-enriched uranium and, with the Russians, is building a very large nuclear power plant at Bushehr that will use more than 100 tons of it, though that will be under international safeguards. Tehran also has a long history of buying atomic materials on the global black market.

"It's reasonable to be concerned about this issue," said Gary Milhollin, director of the Wisconsin Project on Nuclear Arms Control, a research organization in Washington. "Once a country is operating 1,000 centrifuges, you have to worry about the possibility that they could quickly make a bomb."

Elaine Sciolino contributed reporting from Vienna.