Brown says N-power will benefit the environment
The Prime Minister was speaking to the Confederation of British Industry (CBI) ahead of a final decision to be announced early next year after a consultation process.
Greenpeace, which won a court battle to force the consultation period to be extended after claiming the government had already made its mind up, accused Mr Brown of being "obsessed with nuclear power" and warned its lawyers were considering further action.
Scotland's energy minister, Jim Mather, underlined the SNP administration's opposition to nuclear energy, saying the "risks and uncertainties in terms of waste disposal, decommissioning, security and health concerns, or cost, are far too great".
At the CBI's conference, Mr Brown said: "We must - and will - take the right long-term decisions to invest now for the next generation of sustainable and secure energy supplies. We have said that new nuclear power stations potentially have a role to play in tackling climate change and improving energy security."
A Greenpeace spokesman said: "The government seems to try to word their pro-nuclear speeches and propaganda in such a way they won't fall foul of the courts again. But this consultation has been largely a farce again."
A Royal Society of Edinburgh inquiry into energy supply warned there was the danger of a shortfall in electricity with the closures of Hunterston, in 2011, and Torness, due to be decommissioned in 2023, along with coal-fired Cockenzie, due to shut in 2015.
Professor Maxwell Irvine, who chaired the inquiry committee, said he believed Scotland should build new nuclear facilities to help the fight against climate change until new hydrogen technologies become available.
"I'm advocating nuclear now because I see it as a lesser of a whole range of evils, but it's not the long-term answer," he said.
Modern nuclear plants could be built at Torness and Hunterston, but British Energy said priority for new facilities is likely to be given to the existing stations it runs south of the Border.
A spokeswoman said: "We still believe that Scotland is a good place for new nuclear. But in terms of priorities, we will put our new nuclear when we decide to do it where it is best received and in areas of the greatest need, where there is the highest population and lowest current supply.
"That probably wouldn't be Scotland. At the moment Scotland is a net exporter."
• THE world's first commercial nuclear power station opened at Calder Hall in Sellafield in 1956. But public confidence was shaken by a fire in 1957, which saw radioactive material released into the environment, forcing farm produce to be destroyed. The 1973 oil crisis made nuclear increasingly attractive, but accidents at
Three Mile Island in the United States in 1979 and Chernobyl, Russia, in 1986 dealt a fresh blow to the industry. Nuclear energy is back on agenda due to record oil prices and concern over gas supplies, but also as it is seen as a way to cut carbon emissions.