What do a six-ton superconductor and the world's largest laser have in common? Both are fundamental components in two very different approaches to harnessing the energy of nuclear fusion reactions.
The superconductor will be used by the International Thermonuclear Experimental Reactor (ITER) Organization for their magnetic confinement fusion (MCF) reactor1 and the laser will be used by the National Ignition Facility (NIF) for their inertial confinement fusion (ICF) reactor.2 While it's too early to tell if MCF or ICF will be the technology of choice in fusion power plants of the future, both technologies have the potential to provide abundant, clean, and safe electrical energy.
MCF and ICF technologies differ in the way they address what is known as the Lawson criterion, first described by John D. Lawson in 1957.3 The criterion describes the density and confinement time of superheated hydrogen atoms (CAS Registry Number® 12385-13-6) required for fusion reactions to occur; superconductor-generated magnetic waves are used in MCF reactors and laser-generated compression forces are used in ICF reactors.4
Regardless of the confinement technology used, MCF and ICF reactors must heat hydrogen atoms in excess of 180 million degrees Fahrenheit so that the atoms combine, or fuse, to form helium atoms (CAS Registry Number 7440-59-7). According to Einstein's mass-energy equivalence formula, E=mc2, the balance of a nuclear fusion reaction is energy, and more importantly, abundant energy from a relatively small mass of starting material.5 In fact, the U.S. Department of Energy estimates that with hydrogen-fueled fusion reactions:
- "One gallon of seawater would provide the equivalent energy of 300 gallons of gasoline; fuel from 50 cups of water contains the energy equivalent of two tons of coal."6
While the benefits of fusion power are likely still many years off, its promise can be seen 93 million miles away, where the Lawson criterion has been addressed for billions of years in a fusion reactor known as the sun.
Peter S. Carlton, Ph.D.
You can use SciFinder® or STN® to search the CAS databases for
additional information about nuclear fusion, magnetic confinement fusion, inertial confinement fusion, and the Lawson criterion. If your organization is enabled to use the web version of SciFinder, you can click the SciFinder links in this article to directly access details of the substances and references.
- ITER. http://www.iter.org/ (accessed June 11, 2009).
- National Ignition Facility & Photon Science. https://lasers.llnl.gov/ (accessed June 11, 2009).
- Lawson, J.D. Some Criteria for a Power Producing Thermonuclear Reactor. Proc. Phys. Soc. (London) 1957, 70B, 6-10.
- FusEdWeb. http://fusedweb.llnl.gov/ (accessed June 11, 2009).
- Einstein, A. Principle Points of the General Theory of Relativity. Annalen der Physik (Berlin, Germany) 1918, 55, 241-244.
- U.S. Department of Energy, Office of Science, Fusion Energy Science Program. http://www.science.doe.gov/ofes/ (accessed June 11, 2009).
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