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Enrico Fermi.

Photo by: United States Department of Energy, in the public domain

Our solar system’s sun has been fusing hydrogen into helium in its core at 14 million degrees Celsius for 4.6 billion years and counting. That’s an awfully high bar for Earth-bound nuclear fusion enthusiasts to measure up to, but a team of Chinese scientists is making waves after successfully sustaining fusion for 102 seconds at a temperature of nearly 50 million °C with a device that they have dubbed an “artificial Sun.”

Currently, the nuclear power industry supplies over one-tenth of the world’s electricity by harnessing the energy released in nuclear fission, which involves the splitting of heavy atoms: commonly uranium-235 and plutonium-239. The downsides of fission are well-established – aside from operational safety concerns, some waste from nuclear power plants will remain radioactive for thousands of years, and other waste can potentially be weaponized.

Sustaining a fusion reaction, however, has proven to be far more difficult than sustaining a fission reaction. While Enrico Fermi was able to build the world’s first critical-mass nuclear reactor in a basement lab at the University of Chicago in 1942, and various home aficionados have built functional prototypes in garages and sheds, overcoming fusion’s temperature barrier – the millions of degrees necessary to slam deuterium into tritium to make helium – has proven to be much more difficult. This is in part why so-called “cold fusion” became a sensation in 1989 – if it had been legitimate, room-temperature fusion releasing measurable heat might have revolutionized energy production.

The Chinese “artificial Sun” achievement comes at a time when various nuclear fusion collaborations are pursuing multiple techniques for confining and sustaining the high-temperature plasma conditions necessary for fusion. The most common type of experimental device is the tokamak, the kind used by the Chinese team at the Experimental Advanced Superconducting Tokamak (EAST) project.

The idea of the tokamak is to confine a hot plasma current in a toroidal (donut-shaped) path without cooling. The engineering downside, unfortunately one that researchers have been grappling with for almost 60 years, is that particles can drift through magnetic field lines, cooling the plasma and damaging the tokamak. The benchmark hit by the EAST project may provide new insights into avoiding these twin problems.

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A Tokamak reactor.

Photo by: Doug Zwick, Flikr

Energy may not even be the only field that could be revolutionized by nuclear fusion. A team of Russian scientists recently tested a technology for using fusion to destroy cancer cells – tumor cells soak up boron-10 much faster than normal cells, and energy release from the subsequent fusion reaction triggered by neutron bombardment literally rends the cells apart.

Nowadays, though cold fusion may have been a pipe dream, hot fusion still has ample staying potential.  From stalwart tokamaks, to fancy stellarators, to all manner of “magnetic confinement bottles,” fusion energy technology is moving right along as nuclear fission devices age, and that’s reason enough for optimism towards a new nuclear renaissance.

Sources
China’s nuclear fusion breakthrough produces ‘artificial sun’ – http://www.ibtimes.co.in/chinas-nuclear-fusion-breakthrough-produces-artificial-sun-671042
Nuclear Power Today – http://www.world-nuclear.org/information-library/current-and-future-generation/nuclear-power-in-the-world-today.aspx
Radioactive Waste – Myths and Realities – http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-wastes/radioactive-wastes-myths-and-realities.aspx

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