Cold Fusion Breakthrough
heralds clean nuclear power Jonathan Leake, Science Editor
Sunday Times (London), 3 March 2002
NUCLEAR scientists will this week announce they may have achieved a
controlled form of cold fusion, a technology that potentially offers
humanity a limitless source of clean energy.
The researchers are to publish evidence suggesting they have successfully
fused the nuclei of hydrogen atoms, so recreating the processes that take
place within the sun.
Until now the only way to achieve fusion has been through nuclear weapons or
in vast experimental machines that cost billions of pounds. Both depend on
generating extremely high temperatures. However, the latest research, by
scientists at the American government's Oak Ridge National Laboratory and
the University of Michigan, was done on a laboratory bench using relatively
simple and cheap equipment at room temperature. The study echoes the work of
Professor Martin Fleischmann and Stanley Pons who, in 1989, announced they
had achieved cold fusion at Southampton University but were ridiculed when
no one could repeat their work.
Fleischmann and Pons made what many now see as a fatal mistake when they
released their results at a press conference rather than having them
scrutinised by other scientists before publication in an academic journal.
It is understood that Rusi Taleyarkhan from Oak Ridge, Fred Becchetti from
the University of Michigan and their collaborator, Robert Nigmatulin, of the
Russian Academy of Sciences, have repeated their work and subjected it to
extensive peer review.
If confirmed, the discovery could rank among the most important since the
dawn of the nuclear age. The scientists are, however, extremely cautious at
this stage, saying only that they have detected all the signs of fusion
rather than categorically confirming it. Their technique uses pressure waves
to generate tiny bubbles in a solution of acetone that has been infused with
deuterium, a "heavy" form of hydrogen extracted from sea water.
At the heart of most hydrogen atoms is a nucleus comprising a single proton.
Deuterium atoms, however, have an additional particle, a neutron. This makes
them roughly twice as heavy and slightly unstable. Physicists have long
known that smashing two deuterium atoms together can fuse them into tritium,
a third form of hydrogen with a proton and two neutrons. This fusion
releases vast amounts of energy.
This was the
principle used to create the hydrogen bomb in 1945, but ever since then
scientists have been struggling to find a way to control the process. In the
latest technique, the sound waves create bubbles that expand with explosive
force. As the wave passes, the bubbles implode, generating extremely high
temperatures. This process is known as sono-luminescence after the flashes
of light emitted.
Until recently scientists could generate only temperatures of tens of
thousands of degrees, far short of the sun's 10m Celsius. This appears to
have been solved by "hitting" the bubbles with another sound wave that
compresses them so rapidly that temperatures soar and the deuterium fuses.
An insider said the researchers had detected "promising signs of fusion"
including the creation of tritium and, crucially, the emission of neutrons.
The researchers believe the neutrons have energy levels consistent with
those that would be emitted by deuterium fusion.
This would enable them to escape the fate of Fleischmann and Pons, whose
readings of neutrons enabled them to claim they had achieved fusion. It
later emerged that these neutrons could have been the results of
contamination. Neil Turok, professor of theoretical physics at Cambridge
University, said the results, if confirmed, were extremely exciting: "Cold
fusion has a bad history but these laboratories are among the best in the
world and they will have taken every precaution to get it right."
The research has major implications for other fusion projects. Britain
already hosts the Jet project at Culham in Oxford, where a machine has been
built to research sustainable nuclear fusion reactions. This weekend it
emerged that Culham had scrapped its own research into sono-luminescence and
other low-tech forms of fusion after a report from Thornton Greenland, a
former senior scientist, suggesting it was unlikely ever to work.
Greenland said: "I thought there was too little evidence to show it would
work, but this suggests I was wrong." Recently, Lord Sainsbury, the science
minister, committed Britain to joining an international project to build a
£2 billion fusion machine called Iter, Latin for "the Way". Even this,
however, will be able to sustain fusion reactions for only 16 minutes. A
proper fusion reactor capable of producing power is thought to be 30-50
years away.
Fleischmann, who now lives near Salisbury, still believes his results were
correct although he regrets allowing colleagues to press him into
publicising them before he was ready.
He said: "I hope they have achieved it. If they have, I hope people are
ready for it this time."
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