April 8, 2009. Copyright 2009, Graphic News. All rights reserved

Quest for test-tube fusion
By Simon Morgan

LONDON, April 8, Graphic News:  It sounds like something from science fiction, the centrepiece of a Bond villain’s bid for world domination. 

In fact, a project to create a miniature star in a “test-tube”, triggering a scaled-down thermonuclear explosion and paving the way to the possibility of unlimited cheap, safe and renewable power, is the brainchild of the U.S. government’s National Nuclear Security Administration (NNSA), whose day job is maintaining the nation’s nuclear arsenal. 

Following certification by the Energy Department at the end of March, the Lawrence Livermore National Laboratory, 50 miles east of San Francisco, is now embarking on a series of experiments with its $3 billion National Ignition Facility, a decade after work first began on the project. 

The goal, which it hopes to achieve by next year, is the Holy Grail of nuclear physics; the creation of energy through controlled and sustained nuclear fusion -- the process that generates the heat and light of the Sun. 

If the NIF team is successful, the ultimate result could be nothing less than an 11th-hour solution to the twin crises facing a world catastrophically dependent on rapidly diminishing and environmentally harmful fossil fuels. 

Current nuclear reactors utilise fission, the process of splitting the nucleus of a single atom into two. This is an expensive and complicated process fraught with inherent dangers and largely unresolved questions, such as how to dispose of the hazardous radioactive waste left behind. 

Fusion, the process of compressing two nuclei into one, uses easily available materials, yields up to four times as much energy and, producing harmless helium as a byproduct, leaves behind no troublesome radioactive waste. 

The stumbling block to tapping this priceless resource has always been that triggering the process requires the generation of improbably vast amounts of energy. 

Until now. At the heart of the NIF facility is an unparalleled array of 192 lasers, housed in a 10-storey building the size of three football fields. These are capable of delivering 60 times more power than any previous system, producing a burst of two million joules of energy, roughly equivalent to that consumed by five trillion (a million million) 100-watt lightbulbs. 

This raw power is focused on an object the size and shape of a small pea. This is the target -- a hollow plastic sphere containing a mix of deuterium and tritium, the two “heavy” isotopes of hydrogen. 

To ensure the “pea” is bathed evenly in energy, it will be placed inside a “hohlraum”, a hollow, gold-plated cylinder little larger than a drug capsule, into which the ultraviolet beams from the lasers will be directed. The hohlraum absorbs the energy and radiates it back out evenly as X-rays, ensuring a uniform implosion. 

Blink, and you could miss it; the lasers will fire for about 20 billionths of a second, compressing the sphere and its contents to a density 100 times that of solid lead and generating more heat than the heart of the Sun -- 100 million degrees Celsius. 

This is thermonuclear fusion and, say the researchers, it will create “conditions similar to those that exist only in the cores of stars and giant planets and inside a nuclear weapon”. If practice follows theory, the fusion will produce anything between 10-100 times the amount of energy that was used to create it. Next stop -- though some years down the line -- could be the production of commercial power plants. 

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Success is not certain, however, and some doubt it is even possible. The use of the “burn and gain” of nuclear fusion as a viable source of electricity has danced tantalisingly out of reach for half a century and the successful use of lasers in a bid to achieve the “inertial confinement fusion” now being attempted at NIF has remained elusive since the 1970s. 

Nevertheless, the facility has already gone further than any previous attempt and, by next year, it hopes to have gone all the way. On March 10 it became the first project of its kind to break the one megajoule barrier, an achievement hailed by NIF Director Ed Moses as “an incredible milestone on our journey to ignition”. The team, he said, “are well on our way to achieving what we set out to do -- controlled, sustained nuclear fusion and energy gain for the first time ever in a laboratory setting … NIF is well on its way to achieving breakthroughs in science never imagined”.
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There is a political dimension to the programme that guarantees it will continue to receive the support of the Obama administration -- and one that makes it appropriate that it is being orchestrated by the NNSA, guardian of the nation’s utimate military might. Although instituted on another president’s watch, the goal of the NIF dovetails neatly with Barack Obama’s determination to end America’s reliance on Middle East oil. 
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