States sign nuclear energy pact

An international consortium has signed a formal agreement to build an experimental nuclear fusion reactor. The multi-billion-euro project known as Iter - or "the way" in Latin - will aim to produce energy from nuclear reactions like those that fuel the Sun. If successful, it could provide energy that is both clean and limitless.

The project, which will be based in France, follows years of talks between South Korea, Russia, China, the EU, the US, India and Japan. If all goes well, officials will build a demonstration power plant before rolling out the technology to the world. Iter says electricity could be available on the grid within 30 years.

"Fusion could become the dominant source of electricity on Earth in a century or so - we have to work to try to get it," Jerome Pamela of Iter told the BBC.

In a fusion reaction, energy is released when light atomic nuclei - the hydrogen isotopes deuterium and tritium - are fused together to form heavier atomic nuclei.

To use controlled fusion reactions on Earth as an energy source, it is necessary to heat a gas to temperatures exceeding 100 million Celsius - many times hotter than the centre of the Sun.

Read the whole BBC story here. Then answer these questions.

1. Where did the signature take place?
2. What was Mr Jose Manuel Durao Barroso doing there?
3. What will begin in the spring?
4. What will happen in 2009?
5. How do a fusion reaction and a typical chemical reaction compare?