British scientists at the Rutherford Appleton Laboratory near Oxford will this week begin work to create a nuclear fusion reactor. If successful, the reactor will be a prototype for future commercial power stations, providing a cleaner and safer replacement for conventional nuclear power stations with the potential of producing effectively unlimited energy. The fusion reaction only produces very small amounts of low-grade radioactive material and does not carry the risk of radioactive meltdown.

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 that they fuse, producing harmless helium and vast amounts of energy. It is estimated that there is suffiicient deuterium and tritium in the oceans to supply the world’s current level of energy consumption for 300 billion years – a hundred times the life of the Sun.

The National Ignition Facility in Livermore, California, is also aiming to use powerful lasers to create the intense pressures required to trigger a fusion 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. The British project will adapt the American laser approach and improve its efficiency so that it can trigger the reaction at lower pressure and produce a net surplus of energy whcih would be the basis for commercial power production.

Funding for the £1 billion ($au2.3 billion) project will come from the UK government’s Science and Technology Facilities Council and from the European Commission.