"Choices will will have to be made very quickly, because the question of renewing our nuclear installations will have to made from 2020 onwards, which, in the energy field, is practically tomorrow," Nicole Fontaine, a junior industry minister, told an audience in Paris at a discussion of future energy policy options.

But a former environment minister in the Socialist-led coalition government, defeated in a general election last year, said Europe and the market "will kill nuclear", since no investor would buy a new generation of nuclear reactors and some European countries were moving away from nuclear energy.

The idea that France had to choose between nuclear energy and global warming was "stupid", Yves Cochet, a Green member of the National Assembly told the meeting.

Fontaine's remarks were seen as the clearest indication yet that France, which gets almost 80 per cent of its electricity from nuclear power stations, will not abandon its reliance on nuclear.

"It isn't a question of keeping quiet about the risks linked to the use of nuclear power, whether of an accident or proliferation for military uses," she said.

"But these risks have to be compared with the dangers threatening our planet from the greenhouse effect; the choice has to be made between two disadvantages and everyone should know it."

If no decision was taken by 2010 to update French nuclear power stations France would have the choice in 2020 between gas-powered power stations which would emit greenhouse gases contributing to global warming and American nuclear power stations.

"These are not particularly appealing alternatives," a source close to Fontaine said.

Cochet riposted by arguing that the real price of nuclear power, once the cost of disposal of waste and dismantling obsolete reactors was taken into account, was uneconomic.

Nuclear power would not solve the problems of pollution from transport and households.

Earlier this month a French parliamentary committee called on the government to give the go-ahead for two companies to build a prototype Franco-German next-generation nuclear reactor.

The Socialist-led government in power from 1997 to 2002 showed less enthusiasm for the nuclear option than previous administrations, to some degree because of pressure from the environmentalists in the coalition.

Fontaine said the price of oil and gas was certain to rise and claimed that climate change posed "the most serious and urgent problem we face." France had to cut its greenhouse gas emissions by 75 per cent by 2050.

She said that if the pattern of energy production in the US was the same as in France, the US could cut emissions of carbon dioxide, the chief gas involved in global warming, by 30 percent.

SPACE.WIRE