In Fusion, Less Confusion
Though gasoline prices have declined sharply in recent months, the fact remains that there is only a finite supply of oil in the ground, and after that, who knows what our energy-hooked society will do? For more than 30 years scientists have dreamed of nuclear fusion as the ultimate solution, offering an inexhaustible source of energy if only they could figure out how to make it work.
Last month researchers at Princeton University achieved another milestone in the quest to control the fusion reaction and make it a viable energy source. Using their giant Tokamak machine, they achieved temperatures of 360 million degrees Fahrenheit for a split second--10 times hotter than the sun, and sufficiently hot to power a fusion reaction should they get one going. There is no doubt that fusion reactions do occur, fusing hydrogen isotopes and releasing vast amounts of energy in the process. Fusion is the reaction that powers the sun, and it is also the reaction of the hydrogen bomb. But in order to harness the energy and keep it from being destructive, the reaction must be controlled. If that can be done, ordinary seawater could be turned into electricity.
In order to do it, scientists must achieve a certain density and confinement time for the fuel and a sufficiently high temperature. They had previously reached the density and confinement time, and last month they got the temperature. Now they must put all three together simultaneously to achieve “break-even”--a reaction that puts out more energy than it consumes.
This is all encouraging news, of course. It has taken a long time, but the progress is palpable, and scientists now appear to have a controlled fusion reaction within their reach. But there is a long way to go before you will flip a switch in your home and get electricity from fusion. The first fission reaction--splitting atoms of uranium to release their energy--occurred in 1939, and the first chain reaction--the equivalent of break-even--occurred three years later. It took nearly three decades after that--10 times the interval from first reaction to break-even--before the first fission power plants became viable.
Fusion has taken far longer. The first fusion reactions were achieved in the early 1950s, and more than 30 years later break-even has yet to be reached. If it takes 10 times as long to develop the technology for a commercial power plant, in what century should we expect it?
Still, better to try than not, and the latest milestone is a tremendous achievement. Now, on to break-even.
