Sellafield is seen as prime candidate for a new plant
Four potential sites for new nuclear power stations have been proposed as the government's process for choosing suitable locations starts in earnest.
Sellafield in Cumbria, Bradwell in Essex, Oldbury in Gloucestershire and Wylfa in Anglesey have been named by the Nuclear Decommissioning Authority.
The criteria on which sites will be judged will be published on Tuesday, with a decision due later this year.
Ministers say up to 9,000 jobs could be created in building each plant.
Unions representing workers in the nuclear industry welcomed the fact the process for identifying new sites was gathering pace, saying it was "positive news" at a grim time for the economy.
But the Conservatives accused the government of "dithering" over its nuclear policy while the Lib Dems said new nuclear plants were not the answer to the country's long-term energy needs.
Most current UK nuclear power stations will cease operating within the next 20 years, prompting fears of an "energy gap" amid uncertainty about levels of future gas and oil supplies.
In 2006 the government committed itself to building a new generation of plants by 2025 on the condition that they would be financed by the private sector.
The choice of new locations is set to be extremely controversial.
Potential locations for new sites will be put forward over the next few weeks, with the nuclear industry favouring the option of building new reactors on the site of existing or old ones.
Sellafield, Bradwell, Wylfa and Oldbury are the first to be be put forward as candidates, with others expected to follow in the next few weeks.
The four have been proposed by the Nuclear Decommissioning Authority, which owns the land on which they would be built.
Sellafield is home to the UK's nuclear reprocessing and decommissioning facilities.
An existing nuclear plant at Bradwell closed earlier this year while Oldbury's plant is also due to shut down later this year. The plant at Wylfa was opened in 1971.
Sites will be chosen after what the government says will be a rigorous selection process, in which their impact on the local community, environment will be assessed along with safety and financial considerations.
Each site will then have to secure planning permission, with construction unlikely to start before 2015 at the earliest.
So far three private-sector consortia have expressed interest in building new sites and British Energy, one of those, has begun consultation with residents near Bradwell about its plans.
Gordon Brown, who visited Sellafield on Friday, has said up to 9,000 jobs could be created during the construction phase at each plant and 1,000 jobs once the plants become operational.
"Nuclear is crucial to our low carbon future," he said.
"It is crucial to our energy security and at the same time it represents a massive opportunity for the UK economy."
But opponents of nuclear expansion say it is the wrong route to go down and point out that the share of total electricity generated using nuclear power has been steadily falling.
"It is dangerous and expensive and it won't fill the energy gap or help the fight against climate change," said Simon Hughes, the Lib Dems' energy spokesman
"The UK is perfectly placed for a rapid and major expansion of renewable power, which is clean, safe, effective and would create huge numbers of jobs."