MOSCOW -- In a bid to harness what backers say could be a nearly limitless source of clean electric power, an international consortium chose France yesterday as the site for an experimental fusion reactor that will aim to replicate how the sun creates energy.
The planned $13 billion project is one of the most prestigious and expensive international scientific efforts ever launched. But critics say the technological hurdles to be overcome are so vast that the money could be better spent in other ways.
Japan and France, backed by roughly equal factions in the consortium planning the project, had competed fiercely for the prestige and economic benefits of hosting the project. But Tokyo agreed to a compromise: The fusion reactor is to be sited at Cadarache, near Marseille in southern France, while Japan will have the next-largest role in the project. Cadarache has one of the biggest civilian nuclear research centers in Europe.
''We are making scientific history," Janez Potocnik, the European Union's science and research commissioner, said at a news conference in Moscow held to announce the agreement for the International Thermonuclear Experimental Reactor project.
''This is a great success for France, for Europe, and for all of the partners in the ITER," French President Jacques Chirac said in a statement. ''The international community will now be able to take on an unprecedented scientific and technological challenge, which opens great hopes for providing humanity with an energy that has no impact on the environment and is practically inexhaustible."
Fusion is the process of atoms combining at extraordinarily high temperatures that not only provides the energy of the sun and stars but also gives hydrogen bombs their enormous power. The challenge faced by the international project is to control that energy in a self-sustaining reaction in which the heat released by fusion can be used to generate electricity, an engineering feat of daunting complexity.
But the theoretical attractions of the idea are also great. The reactor's main fuel, deuterium, also known as heavy hydrogen, can be obtained from water. The project's website states that Lake Geneva alone contains enough deuterium to meet global energy needs for several thousand years.
Existing nuclear reactors use fission, or the splitting of large atoms, to produce power, a process that leaves waste that remains highly radioactive for hundreds of thousands of years. Fusion reactors, by contrast, would produce minimal waste that would be radioactive for a much shorter period, backers say.
A joint declaration signed yesterday at a meeting in Moscow of representatives of the United States, the 25-member European Union, Russia, China, Japan, and Korea, said the project would explore ''the long-term potential of fusion energy as a virtually limitless, environmentally acceptable, and economically competitive source of energy."
The project is important for ''the rapid realization of fusion energy for peaceful purposes and the stimulation of the interest of succeeding generations in fusion," it said.
The experimental reactor project was conceived at an international summit in 1985 as a showpiece for cooperation during the Cold War. Construction of the reactor is expected to take 10 years to complete. The reactor itself is budgeted to cost about $6 billion and will produce about 10,000 jobs. The rest of the $13 billion is for associated research, a significant portion of it in Japan.
If the project is successful, long-term plans call for a demonstration fusion power plant to be built in the 2030s and the first commercial fusion plant to be built in midcentury.
''As a project of unprecedented complexity spanning more than a generation, ITER marks a major step forward in international science cooperation," said Potocnik, the EU commissioner. ''Now that we have reached consensus on the site for ITER, we will make all efforts to finalize the agreement on the project, so that construction can begin as soon as possible."
Vladimir Kuznetsov, director of the program for nuclear and radiation safety of the Russian Green Cross, said that, ''Russia was the country that initiated this kind of research" half a century ago, but that ''since then nothing spectacular was achieved along that road." He expressed doubt that the project would ever come to fruition.
According to the agreement reached yesterday, the European Union as a whole will cover 40 percent of the cost and France alone will cover another 10 percent. The remaining half will be paid by the other five partners, including the United States, at 10 percent each. France will provide 40 percent of total staffing and Japan 20 percent.