Iranian President Mahmoud Ahmadinejad, center, visits the Natanz Uranium Enrichment Facility some 200 miles south of the capital Tehran, Iran, in this April 8, 2008, file photo released by the Iranian President’s Office. The concept of a nuclear mecca, a go-to place for “safe” uranium fuel in an increasingly nervous atomic age, is gaining traction.

Vienna ? Buffett’s bankroll, Obama’s clout and the partnership of a savvy ex-Soviet strongman may turn the steppes of central Asia into a nuclear mecca, a go-to place for “safe” uranium fuel in an increasingly nervous atomic age.

The $150 million idea, with seed money from U.S. billionaire Warren Buffett, must still navigate the tricky maze of global nuclear politics, along with a parallel Russian plan. But the notion of such fuel banks is moving higher on the world’s agenda as a way to keep ultimate weapons out of many more hands.

Decisions may come as early as next month here in Vienna.

The half-century-old vision, to establish international control over the technology fueling atom bombs, was resurrected in 2003, when Iran alarmed many by announcing it would develop fuel installations — for nuclear power, it insisted. Mohamed ElBaradei, U.N. nuclear chief, then said the time had come to “multinationalize” the technology, to stop its spread to individual countries.

Last month, the new U.S. president gave the idea its biggest boost.

In a historic speech to tens of thousands in Prague, the Czech capital, Barack Obama detailed an aggressive plan for arms control, including setting up an international fuel bank, “so that countries can access peaceful power without increasing the risks of proliferation.”

That’s the fear: The centrifuges that enrich uranium with its fissionable isotope U-235, to produce power-plant fuel, can be left spinning to enrich it much more, producing fissile, highly enriched uranium for nuclear bombs.

Only a dozen nations have enrichment plants, but ElBaradei’s Vienna-based International Atomic Energy Agency (IAEA) foresees nuclear-power use almost doubling in the next 20 years. More and more governments may want the fuel-making capability.

“The real risk is that highly enriched uranium could be acquired by, say, terrorist groups,” Russian government adviser Alexander Konovalov told a conference in Rome on nuclear dangers. “All they need is 50 kilograms (110 pounds) of enriched uranium. All the rest (to make a bomb) can be found on the Internet.”

The IAEA’s 35-nation board of governors is expected to address the issue at its June meeting. A raft of proposals has surfaced, including a German idea to build an IAEA enrichment plant on “internationalized” soil somewhere, to sell fuel to countries committed to nuclear nonproliferation.

“Assurance” is the byword — a desire to assure future Irans there won’t be politically motivated cutoffs of nuclear fuel supplies, and so they needn’t build, at huge cost, their own enrichment plants.

Only one proposal has upfront money behind it, however — the idea advanced by the Nuclear Threat Initiative (NTI), a Washington-based organization founded by philanthropist Ted Turner and former U.S. Sen. Sam Nunn.

Calling it an “investment in a safer world,” investor and NTI adviser Buffett, considered America’s richest man, pledged $50 million to such a bank, provided governments put up an additional $100 million. That threshold was passed in March, most of the money coming from the U.S. and the European Union.

The $150 million would buy enough low-enriched uranium to fuel a 1,000-megawatt power plant, jump-starting a constantly replenished fuel stockpile that would be owned and sold by the IAEA at market prices and on a nondiscriminatory basis.

On April 6, the day after Obama’s address, another piece of that picture fell into place nearly 3,000 miles from Prague, when another president spoke in Astana, capital of the ex-Soviet republic of Kazakhstan.

“If a nuclear fuel bank for nuclear energy was created, then Kazakhstan would consider hosting it,” Kazakh President Nursultan Nazarbayev announced to reporters.