Sellafield is the single most serious threat to Ireland's environment, the Taoiseach, Mr Ahern, said in one of the strongest criticisms of the nuclear reprocessing plant.
Opening the Fianna Fail Ard-fheis in Dublin, Mr Ahern said: "This survival dinosaur of a defunct military-industrial complex is being kept on life-support by the huge write-offs of British taxpayers' funds.
"It has no stand-alone economic justification. It is the triumph of vested interest over economic reality."
He said the Government was "appalled" by the British government's decision to finally clear the way for the opening of Sellafield's new mixed oxide (MOX) reprocessing plant. "It has all the hallmarks of a bad news story hastily released in the midst of a momentous international crisis in the hope that most people would be distracted," said the Taoiseach.
The heightened threat from international terrorists in the wake of last month's attacks on the US meant the existing risks from Sellafield to Ireland were "unacceptably increased".
"The opening of the MOX plant will mean that the Irish Sea is used as a highway for the transport of highly dangerous nuclear fuel to and from nuclear plants around the world," said Mr Ahern.
He had personally conveyed the Government's "implacable opposition" to the decision to proceed with the MOX facility in a conversation last week with British Prime Minister, Mr Tony Blair. "It is not acceptable that the Irish Sea is used as a kitchen sink by the nuclear industry," Mr Ahern told Fianna Fβil Ardfheis delegates at the Citywest Hotel.
Ireland's legal action against Sellafield would be prosecuted with full vigour before the OSPAR convention, a coalition of 14 countries with an interest in pollution levels in the north Atlantic.
Besides OSPAR, the legal action would also be taken to the European Court of Justice and the United Nations.
"This issue will not be allowed to rest. The campaign to close Sellafield - the campaign to stop the MOX plant in its tracks - is only begun.
"It is a campaign that will be waged ceaselessly until it is won," Mr Ahern declared.
The Taoiseach insisted that Aer Lingus had to survive, despite its economic woes in the wake of the September 11th attacks.
"Sooner rather than later I hope and believe that the world will recover from September 11th and its ongoing aftermath.
"We cannot allow a situation to arise where Ireland is no longer readily accessible to and from our main trading and tourism centres," he said.
Six thousand delegates are expected to attend the ardfheis for Mr Ahern's presidential address at 8 p.m. tonight.
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