BBC News reports that The UK government must "get a grip" on spiralling costs and project delays that have plagued the Sellafield nuclear site, located on the far side of the Irish Sea on the Cumbrian coast, approximately 170 km (112 miles) from the northeast coast of Ireland, just 128 miles from Dublin.
The UK's Public Accounts Committee (PAC) said in a report that some decommissioning projects had already been delayed by more than a decade.
It said estimated budget overruns had climbed to nearly £1bn.
The complex in Cumbria includes three old experimental nuclear reactors, four shut down nuclear power plants and thousands of tonnes of radioactive fuel and high-level wastes.
Sellafield is home to 40% of the world's stock of plutonium which is used to make nuclear bombs.
The committee expressed concerns about the government's lack of clarity over what to do with the stockpile.
MPs acknowledged that progress had been made in reducing risk and removing waste.
However, they said the Nuclear Decommissioning Authority, which is responsible for winding down and cleaning up the site in Cumbria, had not reviewed why projects kept running into difficulties.
Sir Geoffrey Clifton-Brown, deputy chairman of the PAC, said that the Department for Business, Energy and Industrial Strategy "needs to seriously get a grip on its oversight of nuclear decommissioning in this country".