The National Ignition Facility (NIF) is a $4 billion US Dollar (USD) structure being built using funding by the US Department of Energy at the Lawrence Livermore National Laboratory, in Livermore, California, in the United States. The National Ignition Facility is an experiment in inertial confinement fusion (ICF), one possible route to fusion energy, which is the same process that generates the light and heat of the Sun. Fusion fuses together light nuclei (like hydrogen, deuterium, or tritium) into heavier nuclei, producing a surplus of energy by releasing energy from the bonds between particles in the nucleus.
Creating a fusion reaction is not easy. In fact, creating a self-sustaining fusion reaction -- "ignition" -- requires tremendous temperatures (tens of millions of degrees) and/or pressures, and has never been done in a controlled way before. Ignition has only been achieved in the uncontrolled explosion of a hydrogen bomb, the most powerful nuclear weapon. Instead of using fusion energy for weapons, the National Ignition Facility aims to achieve ignition in a small fuel pellet using powerful lasers. Some of its results will be used for nuclear weapons research as well, which has caused protest.
The National Ignition Facility has been under construction since 1997, but after a series of setbacks, its completion was delayed to 2009. Its goal is to achieve ignition by 2010. This will be accomplished by concentrating a 500 terawatt blast of laser light onto a fuel pellet just 2 mm across, a shell of deuterium-tritium ice cooled to 18 degrees above absolute zero. The 500 terawatts of power will be delivered in mere picoseconds (trillionths of a second), about 25,000 times the power output of the world's largest power plant (the Three Gorges Dam hydroelectric plant). The yield will be between 2 and 20 GJ (gigajoules).
Scientists at the National Ignition Facility then hope to achieve ignition, demonstrating the feasibility of inertial confinement fusion as a power source. Still, even if all the tests at the facility are successful, it still couldn't serve as a commercial fusion power plant. It would be more of a tset ground and research facility. The main competitor to inertial confinement fusion is magnetic confinement fusion, conducted in experimental tokamak reactors. The International Thermonuclear Experimental Reactor (ITER), being constructed in Cadarache, France for a cost of $9.3 billion USD, is a tokamak reactor. It is expected to be finished in 2018.