The Government will today directly voice its opposition to the British government about its plans to reopen the Thorp nuclear reprocessing plant at Sellafield.
The Thorp plant in Cumbria, which reprocesses spent nuclear fuel to extract plutonium, has been closed since a leak in April 2005, which led to a £500,000 court fine against British Nuclear Fuels.
Minister for the Environment Dick Roche is to meet Alastair Darling, the British secretary of state for trade and industry in London today.
Last night, sources close to Mr Roche said he would urge Mr Darling to close Thorp permanently on the grounds that it is "an unacceptable risk" and is not economically necessary or environmentally sustainable.
The Thorp reprocessing plant is owned by the Nuclear Decommissioning Authority, which is already facing losses of £40 million a year from its 2005 closure.
The authority has a £2 billion annual budget to clean up Britain's nuclear reactors.
It hopes that Thorp will reopen in "early 2007", following the failure to meet two previous deadlines.
The recent British government energy review made it clear that it believes that nuclear power has "a significant role" to play in meeting Britain's electricity needs.
However, Mr Roche is to argue that Britain's decisions on energy will affect Ireland, particularly if Sellafield continues to leak radioactivity into the Irish Sea.
The Radiological Protection Institute of Ireland visited Sellafield in September 2004 and the Wylfa nuclear power plant in north Wales in October 2006.