Energy ministers and officials from 74 countries were in Paris for the two-day meeting on the future of nuclear energy, as global warming and fossil fuel supply concerns renew governments' interest in atomic power.
"It's clear that nuclear energy is regaining stature as a serious option," said Muhammad al-Baradai, head of the International Atomic Energy Agency (IAEA), which organised the conference.
Al-Baradai said the entry into force of the Kyoto Protocol - which commits governments to reduce greenhouse gas emissions - was focusing minds.
Power plants fired by oil, coal and gas are major sources of carbon dioxide and other gases that cause global warming. Kyoto will force plant operators to pay for their pollution, making nuclear power more competitive by comparison.
"In the past, the virtual absence of restrictions or taxes on greenhouse gas emissions has meant that nuclear power's advantage - low emissions - has had no tangible economic value," al-Baradai said. But the Kyoto Protocol "will likely change that over the longer term".
Soaring fossil fuel costs, including the historic highs charted by oil prices over the past year, are a more immediate worry for governments - and a reminder of the petroleum shocks of the 1970s that persuaded countries such as France to intensify nuclear production.
But accidents at Three Mile Island, Pennsylvania, in 1979 and Chernobyl, Ukraine, seven years later, dealt blows to public confidence in nuclear power.
"It's clear that nuclear energy is regaining stature as a serious option"
Although there is still deep public concern about the risk of accidents and transportation and storage of radioactive waste, nuclear advocates say there is also a new awareness that relying on fossil fuels could lead to an even greater environmental catastrophe.
"The climate will probably change no matter what we now do, but we should, at the very least, make every effort to slow it down," said Donald Johnston, secretary-general of the Organisation for Economic Cooperation and Development, in a video statement. "We ignore its importance at our peril."
Green groups, however, insist that nuclear power is not the solution to the climate problem.
"Today, nuclear energy accounts for 17% of electricity consumption and 3% of energy consumption," said Helene Gassin, who heads Greenpeace's energy campaign in France. The climate problem "goes far beyond the electricity issue".
When Finland begins construction of a new reactor later this year, it will become the first western European country to do so since 1991. France plans to start building a new-generation reactor in 2007.
Nuclear plants produce one-third of Europe's electricity, French Industry Minister Patrick Devedjian said, saving greenhouse emissions "equivalent to those of all of Europe's cars".
"America hasn't ordered a new nuclear power plant since the 1970s and it's time to start building again"
US energy secretary
In a message to the conference, US Energy Secretary Sam Bodman said a University of Chicago study showed that nuclear power "can become competitive with electricity produced by plants fuelled by coal or gas", thanks to new technologies delivering more efficient reactors.
Echoing recent comments by US President George Bush, Bodman said: "America hasn't ordered a new nuclear power plant since the 1970s and it's time to start building again."
The real boom in nuclear power is expected to focus on developing countries, particularly in Asia.
China is expected to increase its nuclear production capacity from the current 6.5 gigawatts to 36 gigawatts by 2020, according to IAEA figures, while India plans to multiply its production capacity tenfold and Russia's is expected to double to about 45 gigawatts.