Sizewell C: Councils 'not convinced' by nuclear power plant plans
EDF Energy has been told to reconsider its designs for the new Sizewell C nuclear power station in Suffolk.
The French energy giant wants to build the plant next to existing power stations near Leiston.
It says it will create 25,000 "employment opportunities" and is currently consulting on the proposals.
But, in a joint statement, Suffolk County Council and Suffolk Coastal District Council said a "greater level of detail" on the plans was needed.
The councils said while they support the principal of new power station, they feel there is a "lack of information" more than four years on from the initial consultation.
Concerns raised relate to the impact on traffic, transport and the environment and the plant's design.
Guy McGregor, chairman of the Sizewell C Joint Local Authorities Group (JLAG), said: "There is much more work for EDF Energy to do to convince us that their plans are up to the expectation we place upon them on behalf of the people of Suffolk.
"We are not yet fully convinced that the benefits of EDF's proposals outweigh the impacts on the community."
The building of Sizewell C is estimated to cost up to £18bn and is expected to take nine years.
The current consultation started on 23 November and runs until 3 February.
Under the plans, EDF Energy has proposed a two-village bypass for Farnham and Stratford St Andrew.
Local authorities said they would prefer Marlesford and Little Glemham to also be avoided by traffic.
The Suffolk Preservation Society has opposed the plans, saying the plant would "threaten environmental damage on an unprecedented scale".
EDF said it will "carefully consider" all responses to the consultation.
A third round of consultation is yet to take place.