Saturday, 8 March 2014

The Power of Nuclear Fusion

Our world is in something of a environmental crisis. It seems that our unquestioning use of the Earth's resources, combined with an exploding population, has resulted in changes that could be detrimental to our civilisation: water levels are increasing, natural food resources are running out and our main energy sources won't last a great deal longer.

Because of this, green, sustainable energy is imperative: green, so as to minimise our production of atmospheric carbon-dioxide levels, which is already well above 'safe' levels, according to climatologist Dr James Hansen; and sustainable so that it can meet the demands of an increasing population and their rising standards of living.

For me, all this makes the ITER project of immense interest. Involving 35 nations and costing 13 billion Euros, this large scale experiment aims to demonstrate the potential of nuclear fusion as a source for future commercial energy.

Nuclear fusion is the process that powers our Sun, enabling it to emit the light and heat energy that lights and warms our Earth. Current commercial nuclear power plants generate energy by a process called nuclear fission, which works by splitting a heavy atomic nucleus into two lighter ones. Nuclear fusion, on the other hand, combines two light atomic nuclei into a heavier one. If these processes are carried out with the right types of atoms, they can generate a huge amount of energy.

The fusion process can be carried out by fusing hydrogen nuclei into a helium nucleus. Hydrogen, found in seawater, is abundant on Earth, and, as such, we'd have enough fusion fuel to last millions of years. Furthermore, it produces no carbon dioxide during operation and no radioactive waste that puts so many off nuclear fission.

So why aren't we currently using fusion to generate commercial energy? Unlike fission, fusion requires extremely high temperatures. Creating these conditions and managing them safely is a challenge. Furthermore, producing these high temperatures requires a lot of energy, and although experimental groups have generated energy using fusion before, no experiment has been able to generate an overall surplus of energy.

The ITER machine, currently being built in France, aims to be the first experiment to achieve this. Designed to fuse hydrogen atoms in conditions ten times hotter than the core of the Sun, ITER hopes to generate ten times as much energy as is put in. The construction, which began in 2010, is scheduled to be completed in 2020, with fusion operation beginning in 2027. But, the technological challenges presented by this ambitious project are already resulting in delays, and even if ITER does achieve its goal, there is much more testing to be done before fusion energy can be generated for commercial use. Experts think it unlikely to be available for another 40, 50 or even 60 years.

There is a long way to go before this solution to our energy needs can become a reality, but the ITER project is paving the way.