The new body in charge of cleaning up Britain's civil nuclear sites today pledges to cut the decommissioning time at some stations by 100 years, down to just 25.
But the Nuclear Decommissioning Authority (NDA) predicts that the cost of its work at the 20 nuclear sites across the country is likely to be "significantly" higher than the £56 billion already predicted.
And it warns its ambitious targets, detailed in the NDA's first draft strategy published today, can only be achieved if the government is willing to take prompt decisions on how to store or dispose of nuclear waste.
NDA chairman Sir Anthony Cleaver said he was committed to achieving clean up in a cost effective, safe, quick and environmentally friendly way.
"Our mission is to deliver a world class programme of safe, cost-effective, accelerated and environmentally responsible decommissioning of the UK's civil nuclear legacy in an open and transparent manner and with due regard to socio-economic impacts on our communities," he said.
Sir Anthony added: "The costs of decommissioning and clean up are already substantial and, if other countries' experiences are a guide, projected costs will almost certainly rise. Nevertheless, we are also confident that by introducing competition and encouraging innovation we can, over time, drive these costs down."
The huge cost of the clean up operation will add weight to opponents of nuclear power, which many predict will form part of the government's efforts to reduce carbon emissions.
Although it has no plans to build any more nuclear power stations, ministers have refused to rule the option out - a position that has left many angry.
Liberal Democrat energy spokesman Andrew Stunnel said today's announcement was the "first dose of official realism there has been over the fantastic costs of the nuclear industry".
He said it "blows away" the argument for relying on nuclear power as a way to tackle climate change, and while he accepts the clean up work is necessary, urged the government to ensure it never happened again.
Among the pledges made by the NDA are a commitment to creating new solutions for the disposal of low level waste, and evaluating options for temporarily storing of intermediate level waste (ILW), as well as a consultation to agree end dates for all sites.
It stressed that some of this depends on other government agencies, however, in particular the committee on radioactive waste management (CoRWM) which is due to deliver its recommendations to the government by July next year.
The NDA report says there are "huge benefits" to be had from the early clearance of some stations and the availability of long-term ILM management arrangements but stresses achieving the latter depends on the government taking quick decisions.
"Any delay by the government in taking these decisions would have significant implications for accelerated decommissioning and ILW interim storage, as well as our ability to achieve early site closure and reduce overall cost," it says.