A change in Iran’s nuclear focus?

Uranium for fuel shift noted by U. N.

VIENNA — An apparent slowdown in Iran’s accumulation of its most sensitive nuclear material may have helped put off the threat of a new Middle East war for now, but Tehran’s expanding uranium- enrichment capacity suggests any relief could be shortlived.

By dedicating a big part of its higher- enriched uranium to make civilian reactor fuel, Iran is removing it from a stockpile that could be used to make nuclear weapons if refined further.

This may explain why Israel — assumed to be the region’s only nuclear- armed nation — recently signaled that an attack was not imminent, after months of speculation that it might be.

But the trend that has emerged in U. N. nuclear watchdog reports on Iran this year could be reversible, proliferation experts say: The material can be converted back to uranium gas as long as it has not been introduced into a working reactor.

Doing so “would take a bit of time, but not more than a month or two, using technology the Iranians have already demonstrated that they have mastered,” a Western envoy said.

In addition, Iran’s rapid installation of new centrifuges — the machines that enrich uranium by spinning at supersonic speed — in an underground site gives it the capability to rapidly increase output, analysts say.

Even so, another Viennabased diplomat said the fact that Iran was making reactor fuel from some of its higher- grade uranium was positive in itself.

“Hopefully it could help us buy some time for diplomacy,” the diplomat said.

The question of when and howquickly Iran might be able to assemble a nuclear weapon is hotly debated in theWest because it could influence any decision on military strikes against the Islamic Republic.

The United States and its allies are especially watching how much uranium refined to a fissile concentration of 20 percent Iran is amassing, as this is a short technical step away from the 90 percent level necessary to create nuclearweapons.

Stoking Western alarm, Iran has sharply expanded this enrichment activity — which compares to the 3.5 percent level needed for most nuclear power plants — over the last year to about 33 pounds per month.

By August, Iran had produced more than 400 pounds of 20 percent uranium since this work started in early 2010, nearing the amount needed for one bomb.

But about half had been fed into conversion for making fuel for a Tehran research reactor, or was about to be.

Producing reactor fuel has always been Iran’s stated purpose for refining uranium to 20 percent fissile purity.

The West fears Tehran’s ultimate goal is to develop atom bomb capability, a claim it denies.