Nuclear safety and a new energy source - or failure?

LIVERMORE, Calif. - By the end of 2010, scientists at Lawrence Livermore National Laboratory may be celebrating the realization of a decades-long dream: re-creating the reaction that powers the sun and causes hydrogen bombs to explode.

Or they'll be sitting on one of the biggest failures in the history of science.

The project, called the National Ignition Facility, or NIF, takes up most of a building the size of two football fields. Inside, 192 of the world's most powerful lasers are focused to concentrate unprecedented power into a target of hydrogen atoms, coaxing them to fuse into helium.

The project, at $5 billion, is already more than seven years behind its original completion date and four times over budget. It's running, but hasn't yet achieved its goal of liberating more energy from the fuel than scientists pump in. They are now promising to do it by the end of this year, though a report last week by the Government Accountability Office called that unlikely.

If that doesn't happen, a failure of such size and scope would threaten Livermore's credibility and call into question the mission of the other weapons labs in the post-Cold War era.

In the 1990s, NIF was billed as a way to ensure the reliability of our nuclear weapons without having to test them. The United States stopped testing nuclear weapons in 1992 and signed an international test-ban treaty in 1996. NIF was originally proposed to help the United States lead the world in ending nuclear testing and thus prevent nuclear proliferation.

But more recently, Livermore scientists have been touting it as a stepping-stone to commercial fusion power - potentially a clean and unlimited source of energy - an assertion that critics call a long shot.

Decorating one side of the NIF building is a billboard-size poster with a striking image of a sunrise shining over the surface of a blue planet. The slogan reads, "Bringing Star Power to Earth."

If NIF works as promised, it would create the world's first controlled version of the nuclear fusion that powers the stars. Instead of splitting the nuclei of the largest atoms, the machine will coax the smallest ones to merge. Both fission and fusion convert traces of mass into copious quantities of energy.

In NIF, the actual fusion takes place in a target smaller than a pea.