Campaigners attempting to force the closure of the Sellafield nuclear power station today claimed its existence could jeopardise the health of generations to come.
Warnings were also issued against any move to build further plants across Britain.
At a conference held by Sinn Fein in Dundalk, Co Louth, the party insisted the controversial facilities in Cumbria still posed dangers across the Irish Sea and discussed how to organise its shutting.
Arthur Morgan TD claimed: "This is the most discredited nuclear facility in Western Europe. The people of County Louth and indeed the whole island have always had serious health concerns around Sellafield.
"We want a complete closure of the plant, on a phased basis. We want a proper clean-up operation and we want more openness and no more cover-ups from the British Government on this issue."
Mr Morgan also told how the prospect of new power plants being erected posed grave concerns.
"On a recent visit to Brussells it was evident to me that there is a very large pro-nuclear lobby at work promoting nuclear energy," he said.
"Nuclear power can never be a viable option. The devastation caused twenty years ago at Chernobyl and the after-effects, which will be felt for many more generations should be enough to make us stop in our tracks and think again."
Other speakers at the conference, Sellafied - Still a Danger, included Lennart Varmby, Board Member of the Swedish Energy Agency; George Regan, the Scottish Vice-chair of Nuclear Free Local Authorities and a Dundee City Councillor; and Rea Street, Vice-chair of CND.