In the US, a different approach known as inertial fusion is being perused at the National Ignition Facility (NIF) in California and the Z-Machine in New Mexico. If Iter is like a conventional power station burning fuel for days or weeks at a time, the inertial projects share more in common with the combustion engine.
NIF blasts tiny pellets of deuterium-tritium fuel with a single 500-trillion-watt laser beam. This is a big number; about 1,000 times the power consumption of the United States.
This gargantuan short-lived laser pulse causes the fuel pellet to collapse and detonate, producing a mini-star for a fraction of a second.
The Z-machine takes a different approach, channelling half a trillion watts through a spider’s web of hair-thin wires surrounding the fuel pellet. The result is much the same: a big crunch known as a Z-pinch and the birth of a star.
If a steady stream of mini-stars can be created, then a power station could be constructed. The Z-machine has already achieved fusion in a test run, and NIF hopes to follow in its footsteps in 2010. The challenge will then be to smooth the rough edges of the technology in order to mass-produce economically viable, reliable power stations.
This is no mean feat, but there seems to be no fundamental reason to doubt that it is possible.
When fusion is mentioned, a common reaction in some circles is to say, “It’s always 30 years away, so let’s not invest too heavily”.
In fact, the fusion engineers of 2009 are speaking of building the final generation of experimental reactors now. …