The site overlooks the Irish Sea
It will take over 100 years before the toxic nuclear site at Sellafield is safe, it has been revealed.
A Westminster report claims that the nuclear storage and reprocessing facility, overlooking the Irish Sea, won't be completely clean until 2120.
Anti-Sellafield protester and South Down SDLP MP Eddie McGrady said: "The nuclear waste is a time bomb.
"They are not only producing but importing the dirty stuff from the rest of the world, it is incredible."
But DUP environment minister Sammy Wilson predicted that an increase in usage of nuclear power would reduce dependence on foreign supplies of fuel from volatile and unstable parts of the world.
Reprocessing of spent nuclear fuel is expected to end by 2020 but it will take years for radioactivity levels inside unused reactors to fall to safe limits.
A spokesman for Sellafield Ltd said: "Sellafield isn't a place that can just be closed down. It is about the removal of plant and equipment from the building, it is about decontaminating and knocking them down, that takes decades.
"A lot of work has been done but with a site as complex as Sellafield that will take a long time to do carefully and safely, which is the priority and can't be compromised on."
It has been estimated that it will cost £73bn to decommission all nuclear civilian facilities in the UK.
However, the report from Westminster's Public Accounts Committee warned that the cost of decommissioning these plants was likely to rise because successive governments and the industry found it easy to push costs onto future taxpayers.
The government is reviewing the issue amid rising fossil fuel costs and new plants could be built, although there is no suggestion at this stage that Northern Ireland is being considered as a site.