The World's Biggest Laser Powers Up

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Innovative glass: The glass needed for the laser’s amplifiers was made using techniques developed specifically for the National Ignition Facility. Here are examples of melted and rough-cut neodymium-doped phosphate glass. Credit: Lawrence Livermore National Security, LLC, Lawrence Livermore National Laboratory, and the Department of Energy

Researchers have created fusion in the lab before, but their experiments required more energy than they produced. For example, a system at Department of Energy's Sandia National Laboratories, called the Z machine, uses electricity instead of lasers to compress hydrogen isotopes and produce fusion. A significantly larger version of the Z machine would be needed to generate more energy than it uses. Moses says that the NIF could reach fusion "gain" in just two to three years, well ahead of the more famous ITER fusion project in Cadarache, France, which likely won't be operational until 2018. "This has been a grand challenge for a long time, so hubris is the worst thing," Moses says. "But we think we see our way through it. When we get a [fusion] burn in 2010 or 2011, we'll be in a very exciting place. I think the world will wake up to the possibilities."

Moses is referring chiefly to the possibilities offered by a fusion power plant. Fusion poses no danger of nuclear proliferation, produces little waste, and uses abundant sources of fuel, so it could provide plenty of clean power for many thousands of years. Some say the fuel--hydrogen--is virtually unlimited, although proposed reactors will use tritium, a hydrogen isotope made from lithium, which is scarcer.

The current facility isn't built to generate electricity. But Moses says that with the right funding, a power plant using fusion from a system like the one at NIF could be running in a decade. In contrast, power plants based on the Z machine at Sandia or the ITER system in France are decades away.

Other experts, however, are more skeptical. "If NIF is successfully, they'll still be a very long way from turning this into a practical energy source," says Ian Hutchinson, professor and head of nuclear science and engineering at MIT. For example, he says, a power plant would require the lasers to fire much more frequently than the NIF lasers--5 to 10 times a second, rather than once every couple of days, as is possible now. (Each burst would release energy equivalent to about five kilowatt-hours of electricity: by comparison, an average nuclear power plant generates 12.4 billion kilowatt hours a year, while an average house requires about 1,000 kilowatt-hours per month.)

In contrast, ITER will use magnetic confinement of hot plasma to produce fusion, a system that produces a continuous stream of energy that could be more suited to generating electricity than the very short bursts of energy produced by NIF, he says.

Whether or not it leads to fusion power plants, NIF is significant, says Stewart Prager, the director of the Department of Energy's Plasma Physics Laboratory at Princeton University. The science it will make possible "cannot be done elsewhere," he says.