Tiskane izdaje
Scientists have long sought easier ways to make the costly material known as enriched uranium - the fuel of nuclear reactors and bombs, now produced only in giant industrial plants.
One idea, a half-century old, has been to do it with nothing more substantial than lasers and their rays of concentrated light. This futuristic approach has always proved too expensive and difficult for anything but laboratory experimentation.
Until now. In a little-known effort, General Electric has successfully tested laser enrichment for two years and is
seeking federal permission in the United States to build a $1 billion plant that would make reactor fuel by the ton.
That might be good news for the nuclear industry. But critics fear that if the work succeeds and the secret gets out, rogue states and terrorists could make bomb fuel in much smaller plants that are difficult to detect.
Iran has already succeeded with laser enrichment in the lab, and nuclear experts worry that G.E.'s accomplishment might inspire Tehran to build a plant easily hidden from the world's eyes.
Backers of the laser plan call those fears unwarranted and praise the technology as a windfall for a world leery of fossil fuels that produce greenhouse gases.
Recently, critics petitioned Washington for an evaluation of whether the laser initiative could backfire and speed the global spread of nuclear arms. "We're on the verge of a new route to the bomb," said Frank N. von Hippel, a nuclear physicist who advised President Bill Clinton.
"We should have learned enough by now to do an assessment before we let this kind of thing out."
New varieties of enrichment are considered potentially dangerous because they can simplify the hardest part of
building a bomb - obtaining the fuel. General Electric, an atomic pioneer, says its initial success began in July 2009 at a facility just north of Wilmington, Nor th Carol ina, that is joint ly owned with Hitachi. It is impossible to independently verify that claim because the government has classified laser technology as top secret. But G.E. officials say that they are accelerating plans for a larger complex at the Wilmington site.
"We are currently optimizing the design," Christopher J. Monetta, president of Global Laser Enrichment, a subsidiary of G.E. and Hitachi, said. Donald M. Kerr, a former director of the Los Alamos weapons lab who was
briefed on G.E.'s work, said that it looked like a breakthrough after decades of exaggerated claims. Laser enrichment, he said, has gone from "an oversold, overpromised set of technologies" to what "appears to be close to a real industrial process."
For now, the big uncertainty centers on whether federal regulators will grant the complex a commercial license. The Nuclear Regulatory Commission is weighing that issue and has promised G.E. a decision by next year.
The aim of enrichment is to extract the rare form of uranium from ore. The process is a little like picking through multicolored candies to f ind the blue ones.
The scarce isotope, known as uranium 235, amounts to just 0.7 percent of mined uranium. Yet it is treasured because it splits easily in two in bursts of atomic energy. I f concentrat ions are raised (or enriched) to about 4 percent, the material can fuel nuclear reactors; to 90 percent, atom bombs.
Enrichment is so difficult that successful production is quite valuable. A pound of reactor fuel costs more than $1,000 - less than gold but more than silver.
The first laser flashed to life in 1960. The plan was to exploit the extraordinary purity of laser light to selectively
excite uranium's rare form. In theory, the resulting agitation would ease identification of the precious isotope and aid its extraction.
Soon, scientists talked about using the innovation to shrink the size of enrichment plants, making them far cheaper to build and run. At least 20 countries and many companies raced to investigate the idea. But the fervor cooled by the 1990s as laser separation turned out to be extremely hard to make economically feasible.
Not everyone gave up. Outside Sydney, Australia, Horst St ruve and Michael Goldsworthy kept tinkering with the
idea at a government institute. Around 1994, the men judged that they had a major advance. They called their idea Silex, for separation of isotopes by laser excitation. In May 2006, G.E. bought the rights to Silex.
Mr. Monetta said the envisioned plant would enrich enough uranium annually to fuel up to 60 large reactors. In theory, that could power more than 42 million homes - about a third of all housing units in the United States.
The laser advance, he added, will promote energy security "since it is a domestic source."
In late 2009, as G.E. experimented with its trial laser, supporters of arms control wrote Congress and the regulatory commission. The technology, they warned, posed a danger of quickening the spread of nuclear weapons because of the likely difficulty of detecting clandestine plants.
Late last year, the American Physical Society - the United States' largest group of physicists - submitted a formal petition to the commission for a rule change that would compel risk assessments as a condition of licensing.
This year, nuclear experts, members of Congress and thousands of supporters of arms control wrote the commission to back the society's effort. Many of them cited well-known failures in safeguarding secrets and detecting atomic plants. But the Nuclear Energy Institute, an industry group in Washington, objected.
It said new precautions were unnecessary because of voluntary plans for "additional measures" to safeguard secrets.
A commission spokesman said the petition would be considered next year. In theory, the risk-assessment plan, if adopted, could slow or stop the granting of a commercial license for the proposed laser plant or could result in design improvements.
G.E. did its own assessment and hired Dr. Kerr to lead the evaluation. He and two other former government officials concluded that the laser secrets had a low chance of leaking and that a clandestine laser plant stood a high chance of being detected.
"It's a major industrial facility," Dr. Kerr said of the planned Wilmington complex.
But critics say a clandestine bomb maker would need only a tiny fraction of that vast industrial ability - and thus
could build a much smaller laser. Each year, they note, the enrichment powers of the Wilmington plant would be great enough to produce fuel for more than 1,000 weapons.
When experts cite possible harm from the commercialization of laser enrichment, they often point to Iran. The danger, they say, lies not only in pilfered secrets, but also in the public revelation that a half-century of laser failure seems to be ending. The demonstration of a new technology often begets a burst of emulation because a new window opens on what is possible.
Francis Slakey, a physicist at Georgetown University, noted that the State Department a dozen years ago warned that the success of Silex could "renew interest" in laser enrichment for good or ill - to light cities or destroy them. That moment, he said, now seems close at hand.
