Bringing the sun down to earth: Tom Wilkie reports on a pounds 200m project that will combine high technology with revival in the former East Germany

Tom Wilkie
Sunday 03 July 1994 23:02

Tomorrow, senior civil servants from science ministries throughout the EU will consider a pounds 200m project to tame the energy source that drives the sun. In theory, the project could open the way to generating unlimited amounts of electricity using fuel derived from seawater.

But there is more to this than the prospects for controlled nuclear fusion. If approved, the project will be sited near Greifswald, in the former East Germany, where German and European finance for such a hi-tech project is targeted at ramping up the economic development of the Neue Bundeslander.

If the Germans succeed in securing European agreement for the project, they will have pulled off something of an international coup - for the device to be built at Greifswald represents a marked departure from the technology that has become the European and international orthodoxy. It will also be a remarkable achievement for the senior German scientist in charge of his country's fusion programme, Professor Klaus Pinkau, director of the Max-Planck-Institut fur Plasmaphysik (IPP) at Garching near Munich.

Projects on this scale require not just scientific leadership but also considerable diplomacy and political skills. Professor Pinkau has these in abundance. He has not only been operating on the European scene but, within the complexities of the German federal system of government, he has had to secure the agreement of old Bundeslander, such as Bavaria and North-Rhine Westphalia, which will now miss out on hi- tech investment that they could have had, but which is to go to Greifswald. The project will be funded 55 per cent by the German government and 45 per cent by the European Union.

The goal of nuclear fusion research is to harness the forces that power the sun and stars: when the nuclei of hydrogen atoms merge to form helium, they release vast quantities of energy. The trick has been managed to destructive effect in the hydrogen bomb, but no one has been able to slow the process down so that energy can be extracted in a form that would be useful, say for generating electricity.

The problem is brutally simple. Fusion can only take place when atoms of deuterium (heavy hydrogen) are heated to temperatures of hundreds of millions of degrees centigrade. This creates a plasma in which the electrons are stripped off from their normal orbits round the atomic nuclei. But how to bottle up such an immensely hot plasma long enough for the deuterium nuclei to collide with each other and fuse? The only sort of bottle that can contain such a plasma is one made from magnetic fields.

At Culham Laboratory, near Oxford, the Joint European Torus (Jet) is in its 11th year of operation. Built at a cost of pounds 175m (in 1983 prices) and costing Europe's tax-payers pounds 70m a year to operate, Jet is the world's largest and most advanced refinement of one type of magnetic bottle, known as a tokamak, first developed in the Soviet Union.

The magnetic field inside a tokamak resembles a twisted ribbon which closes round on itself. The plasma is confined inside a doughnut-shaped vacuum chamber. Looping around this, through the centre of the doughnut-ring, are a series of large magnetic coils. These generate a field running round in the direction of the doughnut. The twist is provided by a second magnetic field created by inducing an electric current in the plasma.

But at the IPP, German scientists have been pursuing an alternative design, known as a stellarator. This device was originally proposed by the American physicist Lyman Spitzer in 1951. This also employs a helical magnetic field to confine the plasma like a twisted ribbon. This time however, the twist is provided by the complex geometry of the magnetic coils themselves.

The coils are so complex that stellarators have been almost impossible to build successfully, but they would operate continuously whereas tokamaks are pulsed machines. The Greifswald device, to be called Wendelstein 7-X after a Bavarian mountain, will be massive: 50ft across, 15ft high, and weighing 550 tons.

Professor Pinkau's enthusiasm is in stark contrast to the grudging, reluctant acceptance of Jet by British scientific administrators. It is an open secret that, now they have got rid of the fast breeder reactor, the next item to be cut from Britain's energy research programme is fusion. There is no sense anywhere in the UK system that Jet might represent a golden opportunity for British engineering to develop new skills which could then be applied to making hi-tech goods for sale elsewhere.

For Professor Pinkau, on the other hand, Wendelstein 7-X is worthwhile not only in terms of fusion research: 'To be a scientist carries a social responsibility - to do something for curiosity alone is not defensible. The construction of the stellarator at Greifswald is to be seen also as an infrastructure development.' The aim will be to create employment and encourage high technology industry in the region.

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