After two decades of talks, negotiations and wrangling more than 30 countries have signed an accord to build a completely new kind of nuclear reactor based on nuclear fusion.
The agreement, signed yesterday in Paris, is hugely important, not alone for its monumental €10 billion price tag. If successful, the planned reactor will produce vast amounts of electricity from near limitless, inexpensive fuel supplies without producing tonnes of the greenhouse gas carbon dioxide. It sounds almost too good to be true in these days of uncertainty over continuity of oil supplies, the threat of global warming and the looming strictures of the Kyoto protocol on climate change. Yet there are no guarantees that the investment will deliver anything at all. Decades of fusion research have so far failed to produce a reactor that gives off more energy than it consumes.
All existing nuclear reactors are based on nuclear fission, the splitting apart of heavy atoms to produce smaller ones. Fission produces lots of heat energy that can be converted to electricity. Yet these reactors also provoke safety concerns - given the catastrophe of Chernobyl and fears over the highly radioactive liquid wastes stockpiled at the Sellafield nuclear reprocessing plant in Cumbria. The Government and the Irish public have turned their faces against nuclear fission despite our exceptional dependency on imported energy supplies.
Nuclear fusion is a different matter. This involves the joining together of two kinds of hydrogen atoms to form helium, a copy of the energy system used by the sun. It is wrong to claim fusion produces no radioactive waste, but the volume and nature of the material produced is far less dangerous than fission. Carbon dioxide output is also involved, but mainly during the construction phase from fossil fuels used for transport and cement production. The enormous technical challenges include maintaining the reactor's operating temperatures at 100 million degrees.
The agreement signed yesterday opens the way to build the first self sustaining nuclear fusion reactor, the International Thermonuclear Experimental Reactor (Iter) at Cadarache, near the French city of Marseille. The EU, US, Japan, India, Russia, South Korea and China have agreed funding , with construction to begin in 2008. If the technical challenges can be overcome, Iter could begin producing electricity by 2016.
Iter is a laudable international effort. If it succeeds it will deliver power and an escape from the carbon dioxide belched out by fossil fuel energy production. Critics argue that a commercially viable reactor could be 50 years away, if indeed one can be built at all. Our environment may have passed a tipping point by then, with the loss of polar ice and sea-level rise as a consequence of an overheated planet. To do nothing is not an option. The world must take action to curb greenhouse gas production while sustaining electricity supply. Fusion may offer a means of achieving both.