Lasers may enable fusion

Can a swimming pool's worth of water power California for a year?

The answer is yes, assuming all goes according to plan for scientists working on laser-driven fusion, said Ed Moses at Lawrence Livermore National Laboratory. Moses spoke at the annual meeting of the American Association of the Advancement of Science, AAAS, on Sunday.

The sun's heat and light get generated in a fusion reaction, in which two hydrogen atoms combine to make helium. This reaction is driven by gravity, whereas in the proposed fusion reactor, particles come together because of lasers.

Water is the main and virtually limitless ingredient, since the idea is to make use of hydrogen particles in water. This summer and fall, researchers hope to test their technique with tritium, a radioactive isotope of hydrogen that has one proton and two neutrons.

Energy from this fusion machine would be harnessed as follows: The reaction produces neutrons, which are slowed down in a liquid salt. The salt gets hot, and then it's pumped as a heat exchanger, essentially making steam. There are also other advanced ideas about how to get the energy out of the process, including the induction of electric currents.

The capability to get more energy out than is put in should be available in about five to seven years, Moses said. Researchers hope to get a demonstration plant up and running in the next 10 to 15 years.

There are, of course, social challenges in addition to technical challenges, he said. Fusion is one of many approaches being considered for cleaner energy.

To learn more, visit the site of the Laser Inertial Fusion Engine.