Scientists Closer To Producing Nuclear Fusion
July 24, 2001
Back during the energy crisis of the 1970s, scientists dreamed of the ultimate source of power -- nuclear fusion. It is the process which gives the Sun its heat and light. And harnessing it would provide an almost infinite supply of power at low prices and without pollution.
But finding an economic way of harnessing it has proved for decades to be one of the most vexing problems in applied physics. Nevertheless, scientists have been quietly making progress.
- This month, scientists at the DIII-D National Fusion Facility in San Diego nearly doubled the usual attainable pressure of hot gaseous fuel inside a doughnut-shaped "Tokamak" reactor -- a critical step in being able to reach conditions necessary to trigger and sustain a fusion reaction.
- But the problem remains of maintaining the pressure for longer than a two-second pulse.
- Fusion requires heat and pressure intense enough to force positively-charged nuclei from a mixture of hydrogen isotopes to overcome their natural inclination to repel each other -- and instead fuse to become helium, releasing energy in the process.
- In order for the nuclei to overcome their powerful repulsive forces and collide, temperatures of hundreds of millions of degrees Celsius must be obtained.
Maintaining a reaction for more than an instant, however, continues to be the elusive step.
The reason scientists continue their quest for this fusion "holy grail" is that it could ultimately produce 100 times more energy than it consumes.
It takes 9,000 tons of coal to produce 1,000 megawatts of electricity. But it would take only one pound of deuterium obtained from seawater to create the same amount of power from a fusion plant.
Source: Guy Gugliotta, "Plans to Harness Fusion May Be Coming Together," Washington Post, July 23, 2001.
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