County Councillors in Cumbria say they want assurances from the government over the future of the Sellafield reprocessing plant.
The Sellafield complex could be stripped from BNFL
The calls follows reports that the government may drop plans to privatise British Nuclear Fuels Limited (BNFL) and strip it of the Cumbria plant.
Tim Knowles, Cumbria county councillor for Frizington and Cleator Moor North, and a former head of corporate affairs for BNFL, said he fears for the plant's long-term future.
But a government spokesman has refused to comment ahead of the publication next month of a draft bill to create the Nuclear Decommissioning Authority (NDA), which is to sited in west Cumbria.
The £48bn body will be tasked with clearing up the radioactive legacy left by 50 years of nuclear power in the UK.
But Mr Knowles said: "This is a very worrying time for Sellafield.
"I think we do have cause to be really concerned and we need some pretty strong guarantees from government."
There are projections that when reprocessing stops, employment numbers will reduce dramatically
Tim Knowles, Cumbria County Council
Trade and Industry Secretary Patricia Hewitt is likely to reveal details of the draft bill in early June.
Some reports suggest she will also say plans for a part- privatisation of BNFL are being shelved.
The bill is expected to pass the entire Sellafield complex, including the controversial MOX fuel plant and nuclear waste storage facilities, to the NDA.
Mr Knowles added: It is usual for leaks to come out ahead of bills, but I am surprised by the depth of what's being said.
"I thought creating the NDA and taking away decommissioning costs from BNFL would make them a really attractive nuclear technology business, with the potential to be at least part-privatised."
Mr Knowles said he had fears for the future of the plant's 10,000 workforce.
He said: "There are projections that when reprocessing stops, probably at the end of the decade, employment numbers will reduce quite dramatically."
Mr Knowles also said he would be concerned if another operator was eventually chosen to run Sellafield.
British Energy and BNFL have recently agreed a reduced deal for the supply and reprocessing of fuel used in British Energy's reactors.
The high price of these contracts was cited as one of the reasons for British Energy's financial problems last year, which led to a bailout by the government.
British Energy has also taken the unusual step of warning its shares are overvalued.
BNFL said it will not comment until after the publication of the draft bill in June.