U.S. scientists have crossed a key step toward controlled nuclear fusion,
atomic process that could result in an inexhaustible source of clean energy and solve problems around fossil fuels and emission of greenhouse gases.

The researchers managed to produce an unprecedented level of energy and break the barrier of megajoule, said the National Nuclear Security Administration of the United States.

“Breaking the barrier of megajoule us closer to the fusion ignition,” said agency administrator, Thomas Dagostino, in a statement.

U.S. scientists managed to produce one megajoule with concentration of 192 laser beams simultaneously at a temperature of 111 million degrees Celsius on a tube the size of a pencil sharpener filled with deuterium and tritium, two isotopes of hydrogen.

“This milestone is an example of the benefits achieved with our nation’s investment in nuclear security and other areas, from advances in energy technology to better  understanding of the universe, “he added.

Nuclear fusion is the engine of the sun and the stars and their artificial production would provide an unlimited choice of clean generation to replace the reliance on dwindling fossil fuel reserves. However, until now controlled fusion technology is an unresolved challenge for researchers because of the very high pressures and temperatures involved.

In the experiment the laser energy was converted into X rays, which compressed fuel to levels of temperature and pressure billions of times greater than Earth’s atmosphere, the statement said.

The process leads to the fusion of hydrogen nuclei, releasing energy from nuclear fusion precursor.

The temperature produced by the device during the few billionths of a second experiment, was equivalent to 500 times the energy consumed by U.S. in that same time.

It is also thirty times greater than that obtained so far by any other process with a group of lasers in the world.

Nuclear energy can be released in two forms: nuclear fission, which already occurs in a controlled and arises from the division of nuclei of radioactive elements and heavy as uranium-and nuclear fusion, which in turn binds (hence the name of fusion) of hydrogen nuclei into helium, the two lighter elements.

Twenty years ago, chemists Stanley Pons and Martin Fleischmann caused a sensation by announcing that they had succeeded in producing a cold fusion, a very coveted by scientists in its search for energy sources, clean and economical.

But the dramatic announcement that lost strength after several scientific research teams failed to seek to replicate the experience.


192 Laser Beams Combined to Form One Megajoule Laser Shot


  1. Statement by Dr. Raymond L. Orbach, Under Secretary for Science and Director, Office of Science, US Department of Energy (22 May 2008) [Back]

  2. Safety and Environmental Impact of Fusion, I. Cook, G. Marbach, L. Di Pace, C. Girard, N. P. Taylor, EUR (01) CCE-FU / FTC 8/5 (April 2001) [Back]

General sources

Iter website (www.iter.org)
JET website (www.jet.efda.org)
National Ignition Facility website (https://lasers.llnl.gov)
PETAL website (www.petal.aquitaine.fr)
HiPER website (www.hiper-laser.org)
The Fusion Power website of the EURATOM/UKAEA Fusion Association (www.fusion.org.uk)
European Fusion Network Information website (www.fusion-eur.org)
Website of the Fusion Energy Sciences (FES) program of the US Department of Energy’s Office of Science (www.er.doe.gov/Program_Offices/fes.htm)
Large Helical Device website (www.lhd.nifs.ac.jp)
HiPER activity, Nuclear Engineering International (November 2008)
Fast track to fusion energy, Michael H. Key, Nature 412, 775-776 (23 August 2001)

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