Cumbria's nuclear industry is preparing for arguably its biggest challenge since it was established in the 1950s.
Work on decommissioning Sellafield is due to begin in April
The Nuclear Decommissioning Authority (NDA) will assume responsibility for the clean-up of the Sellafield nuclear reprocessing complex from 1 April.
It marks the start of work to wind down the site, with the loss of thousands of jobs over the next 10 years.
The government has pledged massive support for the area after the West Cumbria-based NDA begins work.
The arrival of the NDA has been blighted by a row over state help to Sellafield owner British Nuclear Fuels Limited (BNFL).
The European Commission (EC) called into doubt a proposed £40bn transfer of liabilities from BNFL to the NDA.
The trade union Amicus has called for permanent staff to be retrained to carry out the decommissioning work and plans to oppose the outsourcing of any core work.
Amicus general secretary Derek Simpson said: "We need to maximise the number of job opportunities available through the decommissioning process by re-skilling Sellafield workers.
"Unless we start training people now, we are in danger of damaging the whole of UK manufacturing and disadvantaging Sellafield workers and the whole Cumbrian economy.
"Amicus is committed to maintaining our members' terms and conditions at Sellafield - ensuring that pay and pensions provision are not threatened by the outsourcing of work."
The union says permanent staff posts at Sellafield are likely to be cut from 12,000 now to 4,000 by 2011.
The government has pledged to create "high quality jobs" to replace those lost during and after the decommissioning process at Sellafield.