Door opens to new nuclear future

Molly Ball

Friday, June 25, 2004 | 9:16 a.m.

A machine that performs nuclear physics experiments -- the most powerful device of its kind in the world -- has been moved to the Nevada Test Site and will be unveiled Monday.

The machine, which is called Atlas and looks like a giant trampoline, works by shooting a massive electrical shockwave into a tuna-can-sized piece of metal, vaporizing it. The effect of the shock wave on the material is similar to that of a nuclear explosion.

"In the absence of underground nuclear testing, these experiments give scientists the data they need that tells us that the weapons that remain in the U.S. stockpile are safe and still work the way they were designed to," Test Site spokesman Darwin Morgan said.

University of Nevada academic researchers also hope to use Atlas for nuclear fusion experiments.

The government declared a moratorium on nuclear weapons tests in 1992. Meanwhile, America's nuclear weapons have continued to age, and scientists must ensure they are still safe and usable without actually detonating them.

"We've got nuclear weapons that have been sitting at various facilities for 20 years," Morgan said. "What's going on inside them as they sit there? What's happening to the pieces and parts that are subject to the radioactive field? What's happening to the plutonium?"

Over time, plutonium oxidizes and decays according to its fixed half-life.

Morgan compared the situation to a car that's been sitting in a garage for decades. You have to make sure it still runs, but you can't start it up -- so you find ways to test the battery, the ignition, the tires and so on.

In the case of Atlas, the actual parts of the car aren't being tested. Instead, it's like testing sample parts to learn more about how starting the car affects them.

"The surrogate materials mimic a lot of the same characteristics you see in the real stuff when it's in that stage of transitioning from solid to fluid," Morgan said.

Atlas was built at Los Alamos National Laboratory in New Mexico during a five-year period for a cost of about $48 million. After only about a year and a half of operation and just 16 experiments, workers began disassembling it to move it to Nevada for a cost of $20.7 million.

Atlas costs about $6 million a year to maintain and will perform $9 million worth of experiments next year. Morgan said those figures are a fraction of the cost of other nuclear testing devices.

The move of Atlas was mandated by Congress as part of the 2001 budget, Bob Reinovsky of Los Alamos said. The Energy Department decided that scientific work was not divided evenly among the country's major nuclear research labs: Los Alamos; Sandia, also in New Mexico; and Lawrence Livermore in California.

"Averaged over its life, our estimates are that it would be as economical or even more economical to operate at the Test Site," even counting the cost of moving Atlas, Reinovsky said. That's because of Test Site resources -- such as workers for Bechtel Nevada, the private contractor that manages parts of the site -- that Atlas can share with other programs, he said.

Atlas will also be shared with researchers. Two years ago, physicist Richard Siemon left Los Alamos for the University of Nevada, Reno, largely because he wanted to be near Atlas and use it in his work.

"This has been a gleam in my eye for many years," Siemon said.

Siemon plans next year to start his experiments, which he believes will eventually lead to a method of nuclear fusion for energy-generating purposes.

Currently, nuclear energy is produced through fission, the splitting of atoms. Fusion, the combining of atoms, also produces massive amounts of energy -- it is the way the sun and other stars work -- but it is difficult to control and expensive to create. Proponents say fusion produces waste that is less toxic and less concentrated than that from fission.

But scientists have not yet found a way to bring fusion to the "break even" point, meaning it would cost less to create the reaction than the value of the energy the reaction gave off. This is largely because the materials involved must be heated to 100 million degrees (Kelvin or Celsius -- "What's the difference?," he joked).

But Siemon thinks he might have found a way.

"Our experiment would be to see if we can use the electrical power generated by Atlas to heat a nuclear material to thermonuclear conditions," he said.

If Siemon's method works, it would essentially be an upstart "end run" around others' more expensive efforts. Several countries are currently collaborating on a $5 billion project that began in 1992, for example.

Siemon has a four-year, $1 million grant from the Energy Department's Office of Fusion Energy Sciences to conduct one of the preliminary experiments toward his goal.

A few University of Nevada, Las Vegas, scientists are also looking at using Atlas, although none has yet designed a formal experiment.

With the moving of Atlas, the Test Site becomes the location of the preponderance of America's most impressive physics tests.

Three of the four "major high-physics platforms" in the country are now in Nevada, Morgan said: Atlas; the JASPER gas gun; and facilities for subcritical tests, which bring plutonium to the brink of fission without causing a nuclear chain reaction.

The fourth is the National Ignition Facility at Lawrence Livermore.

The concentration of equipment at the Test Site marks its transformation from the days it hosted full-scale bomb tests, Los Alamos' Reinovsky said.

"There is a change in the scope of the kind of scientific activities at the Test Site," he said -- "adding above-ground lab activities to what was really a field test environment."