The assumption for the working lifetime of any new nuclear power station built in the UK was contained in analysis published with the 2006 Energy Review. This is available at:
Plant lifetime was assumed to be 40 years.
The document "Consultation on Funded Decommissioning Programme Guidance for New Nuclear Power Stations" set out a Base Case which includes the assumption that the reactor design will be based on a single station operating for an assumed life of 40 years. The Government response to the consultation confirmed that this should remain the assumption for the Base Case. However it will be open to operators to suggest alternative station lifetimes. Both documents are available at: