The future is bright: harnessing energy of the Sun and the stars

PRINTITER

ITER
From around 150 million kilometres away, the Sun does a very good job of heating planet Earth. How convenient it would be if we could harness the energy that the Sun so clearly has, and use it to power our homes and factories here on Earth. This is exactly what the ITER team is seeking to do with the most ambitious international energy project ever, on Earth. The results could change the world’s energy landscape for good, and for the better.

ITER, meaning ‘the way’ in Latin, has broken new ground in bringing together research teams to form the largest ever international research project. It unites seven international partners and has funding of EUR 10 billion. The EU has been an enthusiastic partner from the start, having been a leader in fusion research historically. It is joined by China, India, Japan, Russia, South Korea and the United States, meaning that over half of the world’s population is represented in this pursuit of fusion energy. This scale of collaboration is comparable only with the International Space Station, and makes ITER a shining example of European research success.

The partners are building a reactor to test the feasibility of fusion power: the energy source of the Sun and the stars. The pioneering reactor is being constructed under the direction of an international team in Cadarache, southern France. The organisation responsible for delivering Europe’s contribution to the project is based in Barcelona.

Traditionally we have used fossil fuels to heat our homes and run factories. But supplies are dwindling and dependence on oil-producing nations is growing. A rise in energy consumption due to economic growth in developing countries and an increased use of transport in industrialised nations has exacerbated concerns about the sustainability of our energy supply. The World Energy, Technology and Climate Policy Outlook forecasts that energy consumption will double between 2003 and 2030. The pressures of our growing energy demands are reflected in record prices on the world markets.

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When atoms collide

In traditional nuclear fission power generation, the nucleus of a heavy atom is split. Turning this approach on its head, ITER will fuse light atomic nuclei together, replicating what happens in the Sun and stars. To produce fusion power, light nuclei – the hydrogen isotopes deuterium and tritium – collide at high temperatures and become fused together to form a heavier nucleus. As they fuse, a small amount of mass is lost and transformed into a release of energy.

To produce fusion, the deuterium and tritium isotopes must be heated to very high temperatures, and the resulting hydrogen plasma must be confined using powerful magnets. High-tech components to generate the strong electromagnetic fields have been designed and tested, and are now ready for demonstration in ITER.

From fossil fuels to fusion

Fusion energy is an attractive prospect. It has an almost limitless fuel supply and is environmentally friendly. Fusion releases no harmful greenhouse emissions into the atmosphere, and creates close to zero long-lived waste.

While the waste from traditional nuclear fission power stations remains radioactive for tens of thousands of years, waste from fusion will lose its radioactivity much more quickly. Only metal parts close to the fusion plasma become radioactive and this radioactivity will decay over several decades, with the possibility of re-use after around 100 years. And producing fusion energy does not involve uranium – the chemical element so often associated with the negative aspects of nuclear fission.

A single fusion power station could generate electricity for two million households, and is significantly more efficient than fossil fuels. The release of energy from a fusion reaction is 10 million times greater than that from typical chemical reactions, such as those that occur when fossil fuels are burned.

Bolder, bigger, better

Scientists have had the most success using a ‘tokamak’ (a Russian word to describe a doughnut-shaped magnetic chamber). The largest existing tokamak capable of operating with a deuterium-tritium fuel mix is the Joint European Torus (JET), located in the UK. JET has produced fusion power at the multi-megawatt level, but only for periods of several seconds. ITER will produce between 5 and 10 times more power than is necessary for keeping the plasma at fusion temperatures, thus proving the feasibility of fusion power. At 24 metres high and 30 metres wide, ITER will have 10 times the volume of JET.

When up and running, ITER will be capable of generating 500 million watts of fusion power continuously for up to 60 minutes. This is enough to power 1.7 million personal computers. ITER’s planned successor, DEMO, will build on this, and once connected to the grid, will produce four times as much fusion power on an essentially continuous basis.

Setting the world on a path to a cleaner energy future

If scientists are to reproduce the fusion power of the Sun and stars to generate energy on Earth, they must meet a number of demanding conditions: the plasma must reach temperatures higher than those in the sun, be dense enough and be confined for long enough for the fusion reactions to be self-sustaining.

These conditions have already been achieved separately. Researchers have heated plasma to temperatures as high as 510 million degrees Celsius, which is more than 25 times hotter than the centre of the Sun.

When ITER begins operating in around 2018, scientists will be able to demonstrate that the necessary conditions can indeed be achieved simultaneously. Ultimately, ITER is enabling a global team of physicists and engineers to optimise the technologies, components and strategies needed for fusion power stations. Once they have done this, the Earth’s energy supply will be as reliable as that of the Sun and the stars. What better present could we offer future generations?