Friends of the Earth has condemned government plans for a possible new nuclear station at Oldbury in South Gloucestershire.
On Wednesday it was announced that plans for the facility would go ahead, along with 10 others around Britain.
But Alan Pinder from Thornbury Friends of the Earth said he believed nuclear power made no sense.
Energy company E.On said it needed to build replacements for power stations which were being decommissioned.
Mr Pinder said a survey had claimed children under five living close to a nuclear power station were more at risk of contracting leukaemia.
"That doesn't sound safe to me.
"It won't give us carbon-free energy because the uranium ores which are dug up are so poor [quality] that it takes more energy to extract the uranium to make the fuel than you get out of it in the power station..." Mr Pinder said.
"I don't think there will be any problem rustling up huge amounts of opposition here against it."
Emily Highmore from energy company E.On said in the next 10-15 years a third of power stations in the UK were going to close and these had to be replaced to stop the lights going out.
"E-On believes nuclear is one of the options to fill the gap. Nuclear power is very much a proven technology. It is low carbon and important to help tackle climate change.
"If we push forward for any development at Oldbury the very first thing we will do is talk to the local public. That's something we have already started to do.
A month-long public consultation period now commences. The government wants the first reactors operational by 2018.
Nine of the 11 locations put forward have previously had nuclear reactors, and the other two are close to Sellafield in Cumbria.
In 2007 more than 1,000 residents near Oldbury who were questioned in a public consultation said they wanted the site left to nature when it is closed down.