The race for fusion power

The world’s largest fusion reactor will be built in Europe despite global competition, the government’s chief scientific adviser Prof Sir David King claimed last week.

The International Thermonuclear Reactor (ITER) project will build a huge reactor that could be the prototype for commercial fusion power stations around the world. With a budget of £7bn (e10bn), ITER’s aim is to achieve sustained fusion power by 2030.

The project involves the EU, Japan, Russia, China, the US and, most recently, South Korea. Where the reactor is built is a major geo-political decision, as the winning nation could become a world leader in fusion technology. There are four sites in competition, Cadarache in France, Vandellos in Spain, Rokkasho in Japan and Clarington in Canada.

Since May the project’s partners have been in discussions to decide where ITER will be located, and a final decision will be made in December.

The EU will propose only one site, and must choose between Cadarache and Vandellos – a decision due to be taken on 27 November.

King, who earlier this year chaired the scientific panel that evaluated the French and Spanish sites, is convinced that an EU site will win because of technical and logistical merit.

‘I believe Europe will get ITER. Both EU sites have very clear advantages. My six-strong panel was unable to decide between the two. Cadarache has a very mature fusion research centre and Vandellos is well placed geographically and has the advantage of lower construction costs.’

King described ITER as the world’s ‘largest ever scientific project’. It will use the same type of magnetic confinement, doughnut-shaped design as the Joint European Torus (JET) reactor at the Atomic Agency’s Culham Science Centre in Oxfordshire, but will be twice its size.

Fusion generates energy by fusing fuel atoms. This occurs under intense pressure and at a temperature in excess of 100 million degrees C. The resulting energy-releasing plasma, an ionised gas, is held in mid-air by magnetic fields because it is so hot that it would damage the walls of the reactor.

ITER’s goal is to produce 500MW for 500 seconds or longer. It would use tritium and deuterium as fuel, with 1kg of this combination producing energy equivalent to 10,000 tonnes of fossil fuel.

The researchers hope that with tritium-deuterium fuel the reactor will generate 10 times as much energy as is required to initiate and sustain the process. Such a breakthrough would lead the way to commercial use of fusion power, but the ITER machine will not be fitted with the technology needed to distribute energy to a national grid. Research at the ITER reactor could last up to 20 years before commercial stations are built.

The creation of ITER raises a question over the continuation of the JET project. Nuclear engineers have been concerned that when ITER begins work in 2005 JET could be closed and the UK will lose its fusion expertise. King has proposed that JET be continued, at least while ITER is being built.

As well as an advocate of fusion power King has publicly supported the continued use of fission nuclear power in the UK. He said that the UK must keep the option open for the use of nuclear power for the foreseeable future. In his view, the UK cannot meet its carbon emission reduction target of 60 per cent by 2050 without nuclear power.