Nuclear fusion energy project could lead to limitless clean electricity

By Richard Gray, Science Correspondent

Last Updated: 12:01am BST 05/10/2008

The power of the sun is to be recreated in a new £1 billion science project which aims to provide a clean and almost limitless source of energy.

British scientists will this week begin work to create a nuclear fusion reactor, which will use the same powerful reactions that take place in the Sun to provide energy and, ultimately, electricity.
Scientists have previously only been able to replicate the reaction inside hydrogen bombs.
Now, however, they believe they are on the verge of achieving controlled fusion in a laboratory for the first time.
Laser beams with enough power to light up every home in Britain for a few microseconds will be used to heat up the nuclear fuel to millions of degrees centigrade in order to trigger the reaction.
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If successful, the reactor will be a prototype for future commercial power stations, providing a cleaner and safer replacement for conventional nuclear power stations, which use nuclear fission to produce energy.
Unlike nuclear fission, which tears apart atoms to release energy and highly radioactive by-products, fusion involves squeezing two "heavy" hydrogen atoms, called deuterium and tritium together so they fuse, producing harmless helium and vast amounts of energy.
Previous attempts to harness fusion have failed due to the huge amount of power needed to start the reaction and keep it running, leading to more power being put into the system than is ever given out. But scientists at the Rutherford Appleton Laboratory, near Oxford, hope their approach will generate useful power for the first time.
Leading a consortium of physicists from across Europe they will tomorrow launch the three year process of planning and designing the High Powered Laser Research (HiPER) facility.
Professor Mike Dunne, director of the central laser facility at the Rutherford Appleton Laboratory and one of the scientists leading the fusion project, said that fusion could provide a safe source of energy with no carbon emissions and plentiful energy supplies.
He said: "HiPER is aiming to bridge the step between proving nuclear fusion is possible and a commercial power station.
"It should prove that a big enough laser can be built, with a high enough repetition rate and efficiency, which are the critical building blocks on the route towards fusion energy."
Fusion reactors are already under construction in the US and France using two separate approaches to creating the intense pressure and heat required to trigger the nuclear fusion reaction.
The National Ignition Facility in Livermore, California, is aiming to use powerful lasers to create the intense pressures required to trigger the reaction when it is switched on next year, but the lasers are so powerful it is likely to use up more energy than it produces, meaning the technology would be useless for a commercial power station.
A separate approach at the International Thermonuclear Experimental Reactor in Cadarache, France, is aiming to use powerful magnetic fields to spark the reaction but this is again not thought to be terribly efficient. The HiPER project will adapt the American laser approach and improve its efficiency so that it can trigger the reaction at lower pressure.
"The National Ignition Facility will prove fusion can be achieved with lasers and we are then the next step," said Professor Dunne.
"If you think of the NIF as being like a diesel engine – the lasers compress the fuel pellet until the pressure causes the fusion reaction to start.
"HiPER is more like a petrol engine where the fuel is compressed a little by the lasers but then a second more powerful laser acts like a spark plug to trigger the fusion reaction."
The researchers have received £13 million for the first phase of the £1 billion project to build the HiPER facility. Most of the funding has come from the UK government funded Science and Technology Facilities Council, together with contributions from the European Commission.
It comes at a time when the Government is facing intense opposition to its plans to build new nuclear fission power stations in order to meet rising energy demands as fossil fuel supplies begin to run low.
Unlike nuclear fission, the fusion reaction produces only produces very small amounts of low-grade radioactive material and does not carry the risk of radioactive meltdown.
Fusion fuel, deuterium and tritium is also readily available in seawater. Just 2lbs of fusion fuel is capable of producing the same amount of energy as 10,000 tonnes of fossil fuel.
A spokesman for the STFC said: "The future location of HiPER is being explored over the next few years, with the UK being a prime candidate."
Martin O'Brien, fusion programme manager at the UK Atomic Energy Authority, added: "Fusion is increasingly recognised internationally as a possible long term clean energy supply. The UK is very much in the leading position on nuclear fusion."