UK plans first nuclear fusion power plan Jonathan Leake

http://www.timesonline.co.uk/tol/news/science/article7034945.ece


From The Sunday Times
February 21, 2010


UK plans first nuclear fusion power plan
Jonathan Leake


BRITISH scientists have drawn up plans to build the world’s first nuclear fusion power station. They say it could be pouring electricity into the National Grid within 20 years.

Nuclear fusion, the power that lies at the heart of the sun, offers the prospect of clean, safe, carbon-free power with a minimum of radioactive waste. But despite decades of research the technical problems have seemed insurmountable.

This weekend, however, Research Councils UK (RCUK), which oversees the British government’s spending on science and technology, has said it believes that many of those obstacles are close to being overcome.

It wants to commit Britain to a 20-year research and construction plan that would see a fusion power station in operation around 2030. Didcot in Oxfordshire is among the sites under consideration for the so-called Hiper project.

“The potential of fusion energy to contribute to the future global energy system is sufficiently large that it should be pursued in the UK,” said a report published by RCUK.

It also follows the recent start-up of America’s National Ignition Facility, in California, which has been designed to demonstrate the principle of laser fusion. There, 192 giant lasers have been installed, collectively capable of generating 500 trillion watts — 1,000 times the power of the US national grid — for a fraction of a second.

That energy will be focused on a tiny fuel pellet of frozen hydrogen which, in theory, should be compressed and heated to 100mC — so hot that the atoms within it start to fuse.

“The world is watching and waiting to see what happens at NIF,” said the report, calling this “a seminal moment” in the development of fusion.

Mike Dunne, project co-ordinator for Hiper, agreed. “The NIF laser is performing well — they have already achieved fusion reactions but so far they are putting in much more energy than they are getting out.

“The crucial test will come this autumn when they ramp up the power. In theory they should start generating more power than they put in and if that happens it will be a clear demonstration to the world that laser fusion is ready to be harnessed. So far the signs are very good.”

The Americans designed NIF for a very different purpose from power generation. Its aim is to simulate nuclear explosions so scientists can carry out weapons research. This means that it can trigger only one fusion explosion at a time.

Dunne’s vision for Hiper is to feed a continual stream of fuel pellets into the reactor, blasting them with lasers in rapid succession to generate a constant stream of nuclear fusion explosions.

“The lasers will crush the 2mm pellet to a hundredth of its size in a billionth of a second, making it 10 times hotter than the middle of the sun,” he said.

Under such conditions the hydrogen atoms that make up the fuel are ripped apart, creating a “plasma” of electrons and hydrogen nuclei which collide and interact at high speed.

Some of these collisions result in the nuclei fusing, forming another element called helium and ejecting a neutron, a sub-atomic particle, which hurtles outwards at high speed.

When the neutrons reach the wall of the fusion chamber they pass through it but are absorbed by a blanket of lithium, heating it up. This heat is then captured and used to make steam that can in turn be used to drive a turbine.

The RCUK report, written by a group of independent fusion experts, suggests such a plant would be big enough to generate large amounts of power. “We think the first demonstration should be around 500MW, comparable to a commercial power station,” said Dunne.

Britain has the infrastructure and the workforce needed for nuclear fusion because it hosts the JET fusion facility at Culham in Oxfordshire.

Perhaps one of the greatest challenges for the Hiper team will be creating an international consortium to join Britain on the project, which would cost several billions of pounds.

In theory RCUK can take the decision on such projects without government approval because it has full responsibility for the way it spends its money, but in reality it would need to work closely with ministers.

The Department of Energy and Climate Change said: “This is something that we would look at as long as it is in the framework of a global project.”