Instant expert

Instant expert: Cold fusion

The future of energy or absurd science fiction?

Cold Fusion

Credit: sxc.hu

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What is cold fusion?

There are two main types of nuclear reaction. The first, used in today’s nuclear power stations, is ‘fission’. It involves splitting a heavy atom, releasing energy in the process. The second is ‘fusion’ and it’s almost the opposite – instead of splitting a heavy atom, scientists combine two light ones. This type of reaction releases the most energy and involves less risk of radioactive byproducts. In fact, nuclear fusion is what powers our Sun and all the stars in our universe. If humans could find a way to tap this potentially limitless energy source, the world’s electricity woes would be solved forever – or so the theory goes. The problem is that atoms tend to fuse only under the dense, hot conditions found within a star. As you can imagine, these conditions are incredibly hard to recreate on Earth. Cold fusion is the counterintuitive idea that this type of nuclear reaction can be brought about at room temperature.

Does it work?

For a brief madcap moment in the late 80s, cold fusion was considered a real possibility. On 23 March 1989, the University of Utah held a press conference to announce that two of its electrochemists, Stanley Pons and Martin Fleischmann, had created a fusion reaction on a bench in their lab. What’s more, they had apparently done it using low-tech equipment. Their experiment involved passing an electric current through a rod of a silver-white metal called palladium sitting in a beaker of heavy water (water enriched with a type of hydrogen). Palladium has the ability to soak up lighter atoms, and the chemists thought these atoms could become so densely packed within the metal that they would fuse together. The media went berserk. The day after the press conference, the Governor of Utah announced $5 million for cold-fusion research, and a new energy era was born. It was to last about five weeks.

What went wrong?

Other labs soon had trouble reliably reproducing results. Pons and Fleischmann had bypassed the usual scientific process, agreeing to stage a press conference before publishing peer-reviewed research. Critics said the chemists had made some basic errors, including failing to use a ‘control’ to test the validity of
the experiment. A fusion reaction should have produced sub-atomic particles called neutrons in vast quantities, but not enough were detected. Finally, scientists debunked the theory at a meeting of the American Physical Society (APS) in May. Before the year was out, the US Department of Energy had released a report dismissing cold fusion as a useful power source.

Is it still a possibility?

To paraphrase University of Maryland physicist Robert Park, cold fusion may be dead, but the corpse has continued to twitch. International conferences are still held on cold fusion, a US naval research centre published a paper on the topic in 2007, and two Italian scientists recently claimed to have built a cold-fusion machine. However, most mainstream physicists dismiss cold fusion as the domain of cranks and crackpots, not real scientists. Hot fusion is a possibility, and scientists are investigating methods of controlling the atoms using magnetic fields and laser or particle beams, but the technology is still a long way from commercial viability.

What the movers and shakers think

Jim Green National anti-nuclear campaigner, Friends of the Earth Australia
“Fusion research has absorbed tens of billions of dollars of research and development (R&D) funding around the world – yet the technology is still embryonic. Of the various fusion concepts, cold fusion is the least promising and most contentious and it doesn’t deserve a cent of public R&D funding.”

Anthony Williams Nuclear and particle physicist, University of Adelaide
“There are some invaluable lessons to be learned from the cold fusion saga. However, the key challenge remains: finding a successful technology that can lead to sustainable hot fusion as an energy source.”

John Boldeman Senior science advisor, Australian Nuclear Science and Technology Organisation (ANSTO)
“The experiments of Pons and Fleischmann in 1989 did not find evidence of cold fusion. There are other techniques that might be described as cold fusion, for example laser fusion. ANSTO is not currently researching cold fusion.”