Jun 01 2009

Celebrating the Promise of Fusion Power

Posted by: Jonathan Marshall

Some 3,500 people assembled on Friday at Lawrence Livermore National Laboratory, long associated with research on the hydrogen bomb, to celebrate a facility that could advance efforts to use the same physical principles to create vast amounts of electrical power for peaceful ends. 

The lab's National Ignition Facility is by every account a stunning scientific and engineering achievement. But to what extent it will convert the promise of fusion power into affordable energy remains a huge question mark. The same is true of its French-based competitor, the International Thermonuclear Experimental Reactor (ITER).

Nuclear fusion, the source of power for the Sun and other stars, is also the source of most power on Earth today in the "fossilized" form of oil and coal that derived from plants. It also drives renewable wind and solar power. But directly creating clean, concentrated and controllable fusion power on earth would be a stunning breakthrough and a giant step forward in fighting global warming.

Fusion proponents say, rightly, that they have made tremendous strides in understanding how to control a source of energy that, by its very nature, fiercely resists control. Critics say fusion power today remains where it has been for the past half century--about 20+ years from becoming a commercial reality. With every yard of progress, the goal posts seems to recede apace.

The $3.5 billion Livermore facility cost nearly triple the original estimate in 1994. It took 7,000 workers, 3,000 contractors and a dozen years to build, and won't be fully operational until 2010. When it gets up to full power, the stadium-sized structure will focus 192 lasers--emitting the same amount of energy consumed by 10 billion 100-watt light bulbs in one second--on a tiny hydrogen target. If all goes well, the hydrogen, heated it to 100 million degrees centigrade, will fuse into helium and release a great deal of energy.

It will require another huge feat of engineering, of course, to turn that energy into usable form at a reasonable cost.

Meanwhile, over in France, an international effort is underway to create a fusion reactor controlled by a magnetic doughnut that squeezes hydrogen until it fuses. The ultimate goal is to generate about 500 megawatts of thermal power, or about 10 times more than needed to run the machine.

Like Livermore's facility, the ITER reactor boasts some amazing statistics. Each of its giant magnetic coils weighs 360 tons, about the same as a fully loaded Boeing 747-300 jet. The reactor as a whole will weigh 23,000 tons, three times the Eifel Tower. It is being built on a platform the size of 60 soccer fields, will require the removal of 2.5 million meters of earth, and will rise 19 stories. It will create temperatures of 150 million degrees centigrade, ten times those at the core of the Sun.

But the ITER reactor, also like Livermore's facility, is running behind schedule and over budget. Its first major experiments likely won't take place until 2025 and the latest estimated cost of construction is about double the $7 billion promised in 2006.

As Scientific American noted, "If ITER succeeds, it will not add a single watt to the grid. . . . and some veterans in the field predict that 20 to 30 years of experiments with ITER will be needed to refine designs for a production plant."

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