Sellafield will be decommissioned over the next 10 years

British Nuclear Fuels Limited (BNFL) wants to sell off its BNG subsidiary, which also operates Calder Hall and Drigg, in Cumbria.

The union Prospect, which represents scientists and engineers, said it had concerns over health and safety issues.

The government has promised a full public debate on its nuclear plans.

Trade Secretary Alan Johnson said he had not yet made a decision on whether BNG could be sold-off.

Mr Johnson has also not ruled out privatising the recently-established Nuclear Decommissioning Agency, which is based in Cumbria.

It is tasked with winding down and making safe ageing nuclear sites.

'Unwelcome upheaval'

Prospect general secretary Paul Noon was at Sellafield on Friday to discuss the situation with on-site representatives.

He said: "The key tests for us will be what will provide the best future for safety, security, the environment and long-term energy policy, and for our members and the communities in which they live.

"From our point of view, we would not have wished to start from this position, particularly so soon after the creation of the Nuclear Decommissioning Agency and British Nuclear Group.

"It is yet another unwelcome upheaval that will cause confusion for our members over their futures and that of the organisation they work for."

He said the union would be seeking the strongest possible guarantees that the "intrusion of the profit motive" would not affect safety or security standards, particularly on the issue of foreign control.